System for inner eyelid treatment of meibomian gland dysfunction

ABSTRACT

A system for treating meibomian gland dysfunction. A controller controls a lid warmer attached onto a patient&#39;s eye to generate heat on the inside of the eyelid to provide conductive heat transfer to the meibomian glands. The application of heat assists in the expression of obstructions or occlusions in the meibomian glands to restore sufficient sebum flow to the lipid layer to treat dry eye. Temperatures at the meibomian glands reach desired levels more quickly and efficiently when heating the inside of the eyelid. Reaching such higher temperature levels may be instrumental in removing obstructions in the meibomian glands. Less time may also be required to reach desired temperature levels when applying heat to the inside of the eyelid. An eyecup may be employed to generate a force on the outside of the patient&#39;s eyelid to improve conductive heat transfer and reduce blood flow in the eyelid that causes convective heat loss. Thus, the application of force can further increase the temperature level and/or reduce the time to reach desired temperature levels for removing obstructions.

RELATED APPLICATIONS

The present application claims priority to U.S. Provisional PatentApplication No. 60/880,850 entitled “Method and Apparatus for TreatingMeibomian Gland Obstructive Disease,” filed on Jan. 17, 2007, which isincorporated herein by reference in its entirety.

The present application is also a continuation-in-part patentapplication of U.S. application Ser. No. 11/434,033 entitled “Method andApparatus for Treating Gland Dysfunction Employing Heated Medium,” filedon May 15, 2006, which is incorporated herein by reference in itsentirety.

The present application is also a continuation-in-part patentapplication of U.S. application Ser. No. 11/434,446 entitled “Method andApparatus for Treating Gland Dysfunction,” filed on May 15, 2006, whichis incorporated herein by reference in its entirety.

The present application is also a continuation-in-part patentapplication of U.S. application Ser. No. 11/434,054 entitled “Method andApparatus for Treating Meibomian Gland Dysfunction,” filed on May 15,2006, which is incorporated herein by reference in its entirety.

The present application is also a continuation-in-part patentapplication of U.S. application Ser. No. 11/541,291 entitled “Method andApparatus for Treating Meibomian Gland Dysfunction Employing Fluid Jet,”filed on Sep. 29, 2006, which is incorporated herein by reference in itsentirety.

The present application is also a continuation-in-part patentapplication of U.S. application Ser. No. 11/541,418 entitled “Treatmentof Meibomian Glands,” filed on Sep. 29, 2006, which is incorporatedherein by reference in its entirety.

The present application is also a continuation-in-part patentapplication of U.S. application Ser. No. 11/541,308 entitled “MeltingMeibomian Gland Obstructions,” filed on Sep. 29, 2006, which isincorporated herein by reference in its entirety.

The present application is also a continuation-in-part patentapplication of U.S. application Ser. No. 11/893,669 entitled “MeibomianGland Illuminating and Imaging,” filed on Aug. 17, 2007, which isincorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The field of the invention relates in general to treatment of mammalianeyes. More particularly, the present invention relates to treatment ofmeibomian gland dysfunction (MGD), which may be either responsible foror be a contributing factor to a patient suffering from a “dry eye”condition. A patient's meibomian glands are treated to aid infacilitating a sufficient protective lipid layer being generated andretained on the tear film of the eye to retain aqueous.

BACKGROUND OF THE INVENTION

In the human eye, the tear film covering the ocular surfaces is composedof three layers. The innermost layer in contact with the ocular surfaceis the mucus layer. The mucus layer is comprised of many mucins. Themiddle layer comprising the bulk of the tear film is the aqueous layer.The aqueous layer is important in that it provides a protective layerand lubrication to prevent dryness of the eye. Dryness of the eye cancause symptoms such as itchiness, burning, and irritation, which canresult in discomfort. The outermost layer is comprised of many lipidsknown as “meibum” or “sebum.” This outermost lipid layer is very thin,typically less than 250 nm in thickness. The lipid layer provides aprotective coating over the aqueous and mucus layers to limit the rateat which these underlying layers evaporate. A higher rate of evaporationof the aqueous layer can cause dryness of the eye. Thus, if the lipidlayer is not sufficient to limit the rate of evaporation of the aqueouslayer, dryness of the eye may result. The lipid layer also lubricatesthe eyelid during blinking, which prevents dry eye. Dryness of the eyeis a recognized ocular disease, which is generally known as “dry eye.”If the lipid layer can be improved, the rate of evaporation isdecreased, lubrication is improved, and partial or complete relief ofthe dry eye state is achieved.

The sebum that forms the outermost lipid layer is secreted by meibomianglands 10 of the eye, as illustrated in FIGS. 1-3 of this application.The meibomian glands are enlarged, specialized sebaceous-type glands(hence, the use of “sebum” to describe the secretion) located on boththe upper eyelid 12 and lower eyelid 14. The meibomian glands containorifices 16 that are designed to discharge lipid secretions onto the lidmargins, thus forming the lipid layer of the tear film as the mammalblinks and spreads the lipid secretion. The typical human upper eyelid12 has about twenty five (25) meibomian glands and the lower eyelid 14has about twenty (20) meibomian glands, which are somewhat larger thanthose located in the upper lid. Each meibomian gland 10 has a straightlong central duct 18 lined with four epithelial layers on the innersurface of the duct 18. Along the length of the central duct 18 aremultiple lateral out-pouching structures 20, termed acini, where thesecretion of the gland is manufactured. The inner lining of each acinus20 differs from the main central duct 18 in that these specialized cellsprovide the secretions of the meibomian gland. The secretions flow fromeach acinus 20 to the duct 18.

While it has not been established with certainty, there appears to be avalve system between each acinus 20 and the central duct 18 to retainthe secretion until it is required, at which time it is discharged intothe central duct 18. The meibomian secretion is then stored in thecentral duct 18 and is released through the orifice of each gland ontothe lid margin. Blinking and the squeezing action of the muscle ofRiolan surrounding the meibomian glands 10 are thought to be the primarymechanism to open the orifice for the release of secretion from themeibomian gland 10. Blinking causes the upper lid 12 to pull a sheet ofthe lipids secreted by the meibomian glands 10 over the other two layersof the tear film, thus forming a type of protective coating which limitsthe rate at which the underlying layers evaporate. Thus, a defectivelipid layer or an insufficient quantity of such lipids can result inaccelerated evaporation of the aqueous layer which, in turn, causessymptoms such as itchiness, burning, irritation, and dryness, which arecollectively referred to as “dry eye.”

Various treatment modalities have been developed to treat the dry eyecondition. These modalities include drops, which are intended toreplicate and replace the natural aqueous tear film and pharmaceuticalswhich are intended to stimulate the tear producing cells. For example,eye drops such as Refresh Endura™, Soothe™, and Systane™ brand eye dropsare designed to closely replicate the naturally occurring healthy tearfilm. However, their use and administration are merely a treatment ofsymptoms and not of the underlying cause. Further, the use of aqueousdrops is generally for an indefinite length of time and consequently,extended use can become burdensome and costly.

Pharmaceutical modalities, such as the use of tetracycline, have alsobeen suggested to treat meibomian gland dysfunction. One such treatmentis disclosed in U.S. Patent Application Publication No. 2003/0114426entitled “Method for Treating Meibomian Gland Disease,” U.S. Pat. No.6,455,583 entitled “Method for Treating Meibomian Gland Disease” toPflugfelder et al., and PCT Publication Application No. WO 99/58131entitled “Use of Tetracyclines for Treating Meibomian Gland Disease.”However, this treatment has not proven to be universally clinicallyeffective, and it may be unnecessary in cases where MGD is the result ofobstruction of the gland without infection.

The use of corticosteroids has also been proposed to treat MGD asdisclosed in U.S. Pat. No. 6,153,607 entitled “Non-preserved TopicalCorticosteroid for Treatment of Dry Eye, filamentary Keratitis, andDelayed Tear Clearance (or Turnover)” to Pflugfelder et al. Again, thisproposed treatment appears to treat the symptoms of dry eye, as opposedto treatment of the underlying cause.

Additionally, the use of topically applied androgens or androgenanalogues has also been used to treat acute dry eye signs and symptomsin keratoconjuctivitis sicca. This is disclosed in U.S. Pat. Nos.5,958,912 and 6,107,289, both entitled “Ocular Therapy inKeratoconjunctivitis Sicca Using Topically Applied Androgens orTGF-beta.” and both to Sullivan.

There is a correlation between the tear film lipid layer and dry eyedisease. The various different medical conditions and damage to the eyeand the relationship of the lipid layer to those conditions are reviewedin Surv Opthalmol 52:369-374, 2007. It is clear that the lipid layercondition has the greatest effect on dry eye disease when compared tothe aqueous layer or other causes. Thus, while dry eye states have manyetiologies, the inability of the meibomian gland 10 to sufficientlygenerate the lipid layer is a common cause of common dry eye state. Thisstate is the condition known as “meibomian gland dysfunction” (MGD). MGDis a disorder where the meibomian glands 10 are obstructed or occluded.FIG. 3 illustrates an example of such obstructions 22, 24 or occlusions22, 24. Plug obstructions 22 can occur in the orifice 16 of the centralduct 18. Alternatively, obstructions and occlusions 22, 24 can occurthat block particular acinus 20. The obstructions or occlusions 22, 24can mean that the meibomian glands 10 are partially blocked or plugged,completely blocked or plugged, or any variation thereof. Obstructionsand occlusions 22, 24 can be in a solid, semi-solid, or thickened,congealed secretion and/or a plug, leading to a compromise, or morespecifically, a decrease in or cessation of secretion. Also, with areduced or limited secretion, the meibomian gland 10 may be compromisedby the occluded or obstructive condition often evidenced by a yellowishcolor, indicating a possible infection state. Alternatively, themeibomian gland 10 may be otherwise compromised so that the resultingprotective lipid film is not adequate for preventing evaporation of theunderlying layers on the eye.

MGD is frequently the result of keratotic obstructions, which partiallyor completely block the meibomian gland orifices 16 and/or the centralduct (canal) 18 of the gland 10, or possibly the acini or acini valves(assuming they do in fact exist) or the acini's junction 20 with thecentral duct 18. Such obstructions 22, 24 compromise the secretoryfunctions of the individual meibomian glands 10. More particularly,these keratotic obstructions may be associated with or result in variouscombinations of bacteria, sebaceous ground substance, dead, and/ordesquamated epithelial cells (see, Meibomian Gland Dysfunction andContact Lens Intolerance, Journal of the Optometric Association, Vol.51, No. 3, Korb et al., (1980), pp. 243-51).

Hormonal changes, which occur during menopause and particularly changingestrogen levels, can result in thickening of the oils secreted by themeibomian glands 10. This may result in clogged gland orifices. Further,decreased estrogen levels may also enhance conditions under whichstaphylococcal bacteria can proliferate. This can cause migration of thebacteria into the glands 10 compromising glandular function and furthercontributing to occlusion, thus resulting in a decreased secretion rateof the meibomian gland 10.

When the flow of secretions from the meibomian gland 10 is restricteddue to the existence of an occlusion 22, 24, cells on the eyelid marginhave been observed to grow over the gland orifice 16. This may furtherrestrict sebum flow and exacerbate a dry eye condition. Additionalfactors may also cause or exacerbate meibomian gland dysfunctionincluding age, disorders of blinking, activities such as computer usewhich compromise normal blinking, contact lens use, contact lenshygiene, cosmetic use, or other illness, particularly diabetes. It hasbeen theorized that the acini 20 of the glands 10 may have valves attheir junction with the main channel of the gland 10. The inventorstheorize that if these valves exist, they may also become obstructed insome instances leading to reduced or blocked flow from the acini 20.These obstructions or occlusions 22, 24 may have various compositions.

The state of an individual meibomian gland 10 can vary from optimal,where clear meibomian fluid is produced; to mild or moderate meibomiangland dysfunction where milky fluid or inspissated or creamy secretionis produced; to total blockage, where no secretion of any sort can beobtained (see “Increase in Tear Film Lipid Layer Thickness FollowingTreatment of Meibomian Gland Dysfunction,” Lacrimal Gland, Tear Film,and Dry Eye Syndromes,” Korb, et al., pp. 293-98, Edited by D. A.Sullivan, Plenum Press, New York (1994)). Significant chemical changesof the meibomian gland 10 secretions occur with meibomian glanddysfunction and consequently, the composition of the naturally occurringtear film is altered, which in turn, contributes to dry eye.

MGD may be difficult to diagnose, because visible indicators are notalways present. For example, meibomitis, an inflammation of themeibomian glands 10, can lead to MGD. Meibomitis may also be accompaniedby blepharitis (inflammation of the lids). While meibomitis is obviousby inspection of the external lids, MGD may not be obvious even whenexamined with the magnification of the slit-lamp biomicroscope. This isbecause there may not be external signs or the external signs may be sominimal that they are overlooked. The external signs of MGD withoutobvious lid inflammation may be limited to subtle alterations of themeibomian gland orifices 16, overgrowth of epithelium over the orifices16, and pouting of the orifices 16 of the glands 10 with congealedmaterial acting as obstructions. In severe instances of MGD withoutobvious lid inflammation, the changes may be obvious, including serratedor undulated lid margins, orifice recession and more obvious overgrowthof epithelium over the orifices 16, and pouting of the orifices 16.

Thus to summarize, the meibomian glands 10 of mammalian (e.g., human)eyelids secrete oils that prevent evaporation of the tear film andprovide lubrication to the eye and eyelids. These glands can becomeblocked or plugged (occluded) by various mechanisms leading to so-called“dry eye syndrome.” While not the only cause, MGD is a known cause ofdry eye syndrome. The disorder is characterized by a blockage of somesort within the meibomian glands 10 or at their surface preventingnormal lipid secretions from flowing from the meibomian glands 10 toform the lipid layer of the tear film. Such secretions serve to preventevaporation of the aqueous tear film and lubricate the eye and eyelids12, 14, hence, their absence can cause dry eye syndrome. Obstructions orocclusions 22, 24 of the meibomian glands 10 may be present over or atthe orifice 16 of the gland 10, in the main channel 18 of the gland 10,which may be narrowed or blocked, or possibly in other locationsincluding the passages from the acini 20 to the main channel 18.

While the present state of the art provides a number of treatments fordry eye, there is a need to treat the underlying cause, as opposed tothe symptom. Many patients suffer from dry eye as a result ofobstructions or occlusions in the meibomian glands. Thus, a need existsto provide effective treatment of the meibomian glands to restore asufficient flow of sebum to the lipid layer of the eye to limit the rateof evaporation of the underlying layers. This includes loosening orremoving possible obstructions or occlusions 22, 24 in the meibomianglands 10. FIG. 2 of the application shows the obstructions orocclusions 22, 24 of FIG. 3 in the meibomian glands 10 removed torestore sebum flow to the lipid layer.

SUMMARY OF THE DETAILED DESCRIPTION

One embodiment of the present invention includes the breakthrough andpreviously unknown method of applying heat to the inner surface of theeyelid to treat dry eye caused by meibomian gland dysfunction (MGD).Applying heat to the inside of the eyelid can effectively andefficiently raise the temperature at the meibomian glands to atemperature sufficient to melt, loosen, or soften more seriousocclusions or obstructions in the meibomian glands. The occlusions orobstructions can then be physically expressed to improve sebum flow fromthe meibomian glands to reduce evaporation of the aqueous layer.

Some patients have obstructions or occlusions in their meibomian glandsthat will not sufficiently melt, loosen, or soften to be expressedwithout attaining heightened temperatures at the meibomian glands. Inmany instances, these temperatures either cannot be achieved whenapplying heat to the outside of the eyelid, or these temperatures may beachievable, but only after applying heat to the outside of the eyelidfor a significant period of time. Heightened temperatures may also onlybe achieved by applying heat at unsafe temperatures that would eitherproduce an unacceptable pain response to the patient or damage to thepatient's eyelid. This is because of the temperature drop between theoutside of the eyelid and the meibomian glands due to conductive heatloss. Heat applied to the outside of the eyelid must conductively travelthrough the eyelid tissue and through the tarsal plate that encases themeibomian glands inside the eyelid. As an example, it may take twenty tothirty minutes for the temperature at the meibomian glands to reach onlya temperature of 41 to 42 degrees Celsius when applying heat to theoutside of the eyelid that will not burn or damage the patient's eyelidor surrounding tissue. Temperatures may need to reach between 43 to 45degrees Celsius, for example, for melting, loosening, or softening ofcertain obstructions or occlusions in a patient's meibomian glands.

Until the present application, it was only known to apply heat to theoutside of the eyelid to treat meibomian gland dysfunction (MGD).Medical professionals would have thought it counterintuitive to applyheat to the inside of the eyelid. It was thought that applying heat tothe inside of the eyelid would risk damage to the eyelid or the eyeballitself. Previous studies of heat application to skin showed that damagecould occur for temperatures at or above 45 degrees Celsius. Thesestudies were conducted on external keratinized skin. The tissue on theinner eyelids is non-keratinized epithelium, and as such, is not as wellprotected from heat as keratinized skin. Thus, one would naturallybelieve that applying heat to the inside of the eyelid would produce apain response at lower temperatures than on the outer eyelid surface.However, it has been surprisingly discovered that applying heat to theinside of the eyelid is not only safe, but effective at dislodgingobstructions and/or occlusions in the meibomian glands as part of a MGDtreatment.

It was hypothesized that heating the inside of the eyelid may provide amore efficient conductive heat transfer to the meibomian glands.Attaining a more efficient heat transfer may allow higher temperaturesto be attained at the meibomian glands and/or in a more efficient timeto melt, loosen, or soften more serious obstructions or occlusions inthe meibomian glands. Heat conduction increases with thinner tissue. Themeibomian glands are located closer to the inside surface of the eyelidthan the outside surface of the eyelid. Further, there is no tarsalplate located between the inside of the eyelid and the meibomian glands.Thus, it was discovered than conductive heat transfer to the meibomianglands is more efficient when heating the inside of the eyelid.

In this regard, an experiment was carried out where heat was applied tothe inside of the eyelid (and more particularly the palpebralconjunctiva) against traditional notions and known principles. It wasdiscovered that heat could be applied to the inside of the eyelidwithout damaging the patient's eye if temperature is regulated. Forexample, it was determined that most patients can tolerate a surfacetemperature of 43-44.5 degrees Celsius without anesthesia and withoutsignificant pain. It was found that some patients could toleratetemperatures over 44.5 degrees Celsius without anesthesia. Further, itwas discovered that heightened temperatures at the meibomian glandscould be attained and in less time when applying heat to the inside ofthe eyelid than to the outside of the eyelid due to more effectiveconductive heat transfer and the proximity of the heating to the eyelidsurface.

While not limiting to the present invention, the ability to effectivelyand more efficiently raise the temperature at the meibomian glands byapplying heat to the inside or inner surface of the eyelid may proveinstrumental in reaching the melting, loosening, or softening points ofobstructions or occlusions. Applying heat to the inside of the eyelidcan also include applying heat to the meibomian glands orifices that arelocated at the inner surface of the eyelid at the lid margin. Theorifices may also be obstructed or occluded. The application of heat tothe inside of the eyelid and proximate or directly to the meibomianglands orifices may also prove instrumental in restoring sufficientsebum flow for the lipid layer. When the term or phrase applying heat tothe “inside” or “inner surface” of the eyelid is referenced in thisapplication, such also encompasses the application of heat to themeibomian glands orifices.

The application of heat may be regulated, meaning that a heating meansor element is controlled to be within the temperatures and means thatare safe for the inner surface of the eyelid and at a sufficienttemperature for melting, loosening, or softening an occlusion orobstruction in the meibomian gland. The heat is maintained for a periodof time sufficient to melt, loosen, or soften the occlusions orobstructions. Either during heat application or after heat applicationis removed, the occlusions or obstructions in the meibomian glands areexpressed to remove obstructions or occlusions thus providing animproved pathway to restore or improve sebum flow from the gland.

In one embodiment, increasing the temperature of the surface of thepalpebral conjunctiva to at least 37 degrees Celsius can begin toprovide therapeutic effect for milder cases of MGD. A therapeutictemperature can be any temperature above body temperature. One preferredrange for treatment is 43 to 45 degrees Celsius, with a target of 43 to44.5 degrees Celsius. A time range to apply heat may be a period between1-10 minutes, and may be limited to a range of 3-6 minutes. Temperaturein this range has been found effective and comfortable to the patientwhen treating MGD.

In one embodiment, the application of heat may be regulated. Regulatedheat can include controlling heat according to a temperature profile.The temperature profile may be a constant temperature, include ramp-ups,ramp-downs, peaks and valleys. Further, the temperature profile mayinclude heat pulses or be modulated with various characteristics,including the use of on/off switching or pulse width modulation (PWM)techniques for example. The use of modulated heat may allow thetemperature to be raised even higher at the eyelid without damages tothe patient's eyelid since the increased temperatures are applied forshorter periods of time. Obstructions or occlusions in the meibomianglands may have melting, loosening, or softening points that are beyondtemperatures that may be applied without the use of modulated heat. Thetemperature needed to melt, loosen, or soften obstructions or occlusionsmay depend on how keratinized the obstruction or occlusion is. Not allobstructions or occlusions have the same melting, loosening, orsoftening points.

By example only, elevated temperatures between 45 and 55 degrees Celsiusmay be possible when applying regulated heat, especially if the eyelidhas been anesthetized. However, heat should always be applied to theeyelid at temperatures that take into consideration the pain response ofthe patient as well as whether damage will occur to the patient's eyelidand/or surrounding tissues. Depending on the severity of the patient'sMGD or the patient's pain tolerance, elevated temperatures may be usedwith patients on an individualized basis when applying heat. It has beenfound that lighter skinned patients can generally tolerate less heatthan darker skinned patients, and darker skinned patients tend toexhibit less inflammation as a result of exposure to the heat. Otherfactors, including humidity, may contribute to a patient's tolerance ofgreater temperatures. For example, humans can generally tolerate heat upto 70 to 80 degrees Celsius in dry saunas where humidity is low.Application of heat in higher humidity environments may cause painand/or burns to occur at lower temperatures.

Severe cases of MGD that cause substantial irritation or risk to thepatient may call for temperatures that would produce category one or twoburns to the patient's eyelid, since these burns generally heal.Temperatures that cause category three burns should be avoided. Insummary, treatment times and/or temperature can be adjusted to accountfor these differences. The present invention is not limited to anyparticular temperature or time ranges as long as therapeutic temperatureis being applied to the meibomian glands.

The regulated heat can be maintained at a therapeutic temperature for atreatment period. The treatment period can be approximately 1 to 10minutes for example. The heat could also be repeatedly applied andmaintained for a desired period of time to keep the occlusion orobstruction in a melted, loosened, or softened state. Either during orafter such treatment by regulated heat, mechanical expression of lipidsand other fluids from the meibomian glands has been found to clearobstructions which have essentially melted or been placed in asuspension state (by virtue of melting materials binding solidstogether).

In one embodiment, after expression of the occlusions or obstructions isperformed, an optional pharmacological agent may be applied to themeibomian gland to promote the free flow of sebum and/or reduce orprevent inflammation or infections of the eye or eyelids. Manypharmacological agents have been proposed for treatment of dry eyesyndrome, any of which may be effective or more effective upon clearingof obstructions within the meibomian glands. Some of the pharmacologicalagents that may be utilized include, but are not limited to: antibioticssuch as topical or oral tetracycline and chemically modifiedtetracycline, testosterone, topical or oral corticosteroids, topicalandrogens or androgen analogues, omega 3 fatty acid compounds such asfish oils, Laennec, enzymes that promote lipid production, agents thatstimulate production of enzymes that promote lipid production, and/orany agent which acts as a secretagogue to enhance meibomian glandsecretion or secretion of other tear components. For example, androgenand androgen analogues and TGF-beta have been reported to act as asecretagogue to enhance meibomian gland secretion.

These compounds are illustrative examples of appropriate pharmacologicalagents, but those skilled in the art will appreciate that otherpharmacological compounds may be utilized.

Also, agents, such as Restasis (cyclosporine A), that replace or promoteproduction of the tear component may also be applied more effectivelyafter treating the meibomian glands according to the present invention.Treating the meibomian glands improves the lipid layer thus reducingevaporation and conserving the aqueous layer. Conservation of theaqueous layer reduces the need for tear substitutes to be appliedthrough tear component agents. Thus, tear component agents may not haveto be used as often when employing the present invention to treat apatient's MGD.

In the course of experimenting with the application of heat to theinside of the eyelid, it was also discovered that convective heat lossesoccur due to blood flow in the blood vessels located inside the eyelid.Blood flow through blood vessels located inside the eyelid producesconvective heat losses. The blood flow serves as a natural “heat sink”provided by the body. Convective heat loss is lessened when applyingheat to the inside of the eyelid than when applying heat to the outsideof the eyelid. This is because fewer blood vessels are located betweenthe meibomian glands and the inside of the eyelid than the outside ofthe eyelid. The meibomian glands are located closer to the inside of theeyelid. However, convective heat loss still occurs when heating theinside of the eyelid. However, it was discovered that if the blood flowwas reduced, convective heat losses could be minimized allowing fortemperatures to be attained and sustained at the meibomian glands in aneven more efficient manner and in less time.

Thus, one embodiment of the present invention also includes the furtherapplication of force to the patient's eyelid in addition to heat. Theapplication of force can further assist in obtaining higher temperaturesmore efficiently inside the eyelid at the palpebral conjunctiva and atthe meibomian gland in a shorter period of time and thus moreefficiently. This is because the application of force may reduce bloodflow to the eyelid to reduce convective heat loss, as discussed above.

Applying force can also result in a more efficient conductive heattransfer from an applied heat source, because the pressure created bythe force causes the heat source to be compressed against the tissue ofthe eyelid. This compression can have several benefits. Compressionspreads out the tissue to which heating is applied thus making itthinner and improving conductive heat transfer. Compression can also“squeeze out” air pockets at the surface of the eyelid due to themicroscopic roughness of skin. Thus, compression of the heat sourceagainst the eyelid increases the surface contact between the heat sourceand the surface of the eyelid (which increases the heat transferequation) to provide a more effective conductive heat transfer to themeibomian glands. This results in the meibomian glands being heated tothe desired temperature level in a shorter period of time due to thesegained efficiencies. Further, increased temperatures may be attainedthat may not have otherwise been obtained, or obtained using less heator thermal energy. Because the heating is located in close proximity tothe eyelid surface and heating is further compressed against the eyelidsurface, heat transfer is very efficient providing for the temperatureat the surface of the eyelid to be very close to the temperature at themeiboimian glands.

The applied force may be regulated, meaning that a force generatingmeans is controlled to be within pressure ranges that are safe to beapplied to the eyelid and at sufficient pressure to allow thetemperature at the meibomian gland to be raised sufficiently. The forcecan also be a constant force and be provided manually. The force may beapplied during heating, after heating, or both during and after heating.In either case, the force may assist in expressing occlusions orobstructions when in a loosened, softened, or melted state from themeibomian glands. The force may include vibratory type forces, includingthose generated mechanically or those using fluid type devices ormechanisms. The level of force needed to express obstructions orocclusions in the glands may be greatly reduced when heat is applied tothe obstructions or occlusions to place them in a melted, softened, orloosened state.

The application of force can also stimulate the movement of fluids orsuspensions of occlusions or obstructions from the glands. The presentinvention can be used with devices, which generally apply a regulatedforce or milking action to the eyelid to express the fluids orsuspensions or to otherwise mechanically stimulate the movement offluids from the glands. In some instances, a small, gentle, continuousforce applied to the eyelid will assist in expression of the fluids andsuspensions. Vibration can also be used when applying forcesimultaneously or immediately after the heating to further assist in theexpression.

Any apparatus, device, or tool can be used to apply heat and/or force tothe eyelids to treat MGD. In one embodiment, a force can be applied tothe outside of the eyelid while heat is applied to the inside of theeyelid to treat MGD. The heating of the inner surface of the upper orlower eyelid can be done by any convenient method. The lids can beheated one at a time or both at once, depending on the time available toremove the occlusions once heated and the device or method to heat beingemployed is removed. Several heat and force application devices aredisclosed.

One device for heating the palpebral conjunctiva is disclosed in U.S.Provisional Patent Application Ser. No. 60/880,850, previouslyreferenced above and to which the present application claims priority.In this application, a lid warmer containing a heating element is placedin-between the eyeball and against the palpebral conjunctiva. Theheating element is energized or powered to generate a heat to the insideof the eyelids when the lens in placed on the eyeball. The lid warmermay also contain an integrated insulator that prevents substantial heatfrom reaching the eyeball and thus protects the cornea and sclera. Theheating element may be biased according to its location in the lidwarmer, and in particular to be located behind the insulator proximatethe eyelid, to produce more heat on the insides of the eyelid than onthe eyeball. The lid warmer may also contain a platform. The platformprovides a handle for insertion or adjustment of the heating element,and an area to encapsulate heating components, including an electricalinterface to allow an attached heating controller to generate anelectrical signal to the heating element to produce a regulated heat tothe inside of the eyelid.

The lid warmer may also be used in conjunction with a device thatgenerates a regulated force to the outside of the eyelid when heat isapplied to the inside of the eyelid. In one embodiment, an eyecup havingan inflatable bladder is placed on the outside of the eyelid while thelens is sitting on the eyeball. The eyecup may include an interface thatallows the eyecup to be placed onto the platform extending from the lidwarmer. In this manner, when the eyecup is engaged onto the platform andthe bladder is inflated, a regulated force is applied to the outside ofthe eyelid, thus compressing the eyelid against the lid warmer at theinside of the eyelid. Thus, the meibomian glands are “sandwiched”between, meaning surrounded by, the eyecup and the lid warmer, whereinthe eyecup applies a force vector towards the lid warmer to create apressure on the eyelid and at the meibomian glands within the eyelid.This assists in loosening obstructions or occlusions in the meibomianglands as well as reduces blood flow in the eyelids to preventconvective heat loss of the heat generated by the lid warmer.

Alternatively, a membrane could be attached to the eyecup and employedto generate force. The membrane could be made of different materials andmaterials that stretch, and are resilient. Several embodiments aredisclosed involving a lid warmer and eyecup to be used to apply heat andforce to the eyelid as part of treating MGD. The present invention isnot limited to any particular type of lid warmer and/or force generatingapparatus or device.

In another embodiment, force and heat can be applied to tissue proximatethe meibomian glands to treat MGD. As discussed above, the applicationof force can further assist in obtaining higher temperatures at themeibomian glands and in a shorter period of time and thus moreefficiently. The application of force can improve conductive heattransfer efficiency and/or reduce convective heat loss. Any apparatus,device, or tool can be used to apply heat and force to the tissueproximate the meibomian glands. The application of force may also allowheat to be maintained for a longer period of time. This is because theapplication of force may reduce blood flow to the eyelid, thus reducingconvective heat loss and increasing conductive heat transfer into theeyelid and to the glands. The heat and/or force applied to the tissuecan be regulated, as discussed above. The force may be applied duringheating, after heating, or both during and after heating. The force canremain after the heat is removed, thus increasing the time before thebody's heat sink effect returns the eyelid to normal temperature. Theapplication of force may also assist in expressing the occlusions orobstructions when in a loosened, softened, or melted state from themeibomian glands.

In another embodiment, force can be applied to the inside of the eyelidand heat applied to the outside of the eyelid to treat MGD. As discussedabove, the application of force can further assist in obtaining highertemperatures at the meibomian gland and in a shorter period of time andthus more efficiently. The application of force can to improveconductive heat transfer efficiency and/or reduce convective heat loss.Any apparatus, device, or tool can be used to apply heat and force tothe outside of the eyelid. The application of force may also allow heatto be maintained on the outside of the eyelid for a longer period oftime. This is because the application of force may reduce blood flow tothe eyelid, thus reducing convective heat loss and increasing conductiveheat transfer into the eyelid and to the glands. The heat applied to theoutside of the eyelid and/or the force applied to the inside of theeyelid can be regulated, as discussed above. The force may be appliedduring heating, after heating, or both during and after heating. Theforce can remain after the heat is removed, thus increasing the timebefore the body's heat sink effect returns the eyelid to normaltemperature. The application of force may also assist in expressing theocclusions or obstructions when in a loosened, softened, or melted statefrom the meibomian glands.

In another embodiment, force and heat can both be applied to the outsideof the eyelid to treat MGD. As discussed above, the application of forcecan further assist in obtaining higher temperatures at the meibomiangland and in a shorter period of time and thus more efficiently. Theapplication of force can improve conductive heat transfer efficiencyand/or reduce convective heat loss. Any apparatus, device, or tool canbe used to apply heat and force to the outside of the eyelid. Theapplication of force may also allow heat to be maintained on the outsideof the eyelid for a longer period of time. This is because theapplication of force may reduce blood flow to the eyelid, thus reducingconvective heat loss and increasing conductive heat transfer into theeyelid and to the glands. The heat and/or force applied to the outsideof the eyelid can be regulated, as discussed above. The force may beapplied during heating, after heating, or both during and after heating.The force can remain after the heat is removed, thus increasing the timebefore the body's heat sink effect returns the eyelid to normaltemperature. The application of force may also assist in expressing theocclusions or obstructions when in a loosened, softened, or melted statefrom the meibomian glands.

In yet another embodiment, heat can be applied to both the inside andoutside of the eyelid to treat MGD. Force can also be applied to theeyelid. As discussed above, the application of force can further assistin obtaining higher temperatures at the meibomian gland and in a shorterperiod of time and thus more efficiently. The application of force canimprove conductive heat transfer efficiency and/or reduce convectiveheat loss. Any apparatus, device, or tool can be used to apply heat andforce to the outside of the eyelid. The application of force may alsoallow heat to be maintained on the outside of the eyelid for a longerperiod of time. This is because the application of force may reduceblood flow to the eyelid, thus reducing convective heat loss andincreasing conductive heat transfer into the eyelid and to the glands.The heat and/or force applied to the outside of the eyelid can beregulated, as discussed above. The force may be applied during heating,after heating, or both during and after heating. The force can remainafter the heat is removed, thus increasing the time before the body'sheat sink effect returns the eyelid to normal temperature. Theapplication of force may also assist in expressing the occlusions orobstructions.

Those skilled in the art will appreciate the scope of the presentinvention and realize additional aspects thereof after reading thefollowing detailed description of the preferred embodiments inassociation with the accompanying drawing figures.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawing figures incorporated in and forming a part ofthis specification illustrate several aspects of the invention, andtogether with the description serve to explain the principles of theinvention.

FIG. 1 illustrates an exemplary upper and lower human eyelid showing themeibomian glands;

FIG. 2 illustrates an exemplary cutaway view of a meibomian gland;

FIG. 3 illustrates an exemplary cutaway view of a meibomian gland havingseveral clogging mechanisms;

FIG. 4 illustrates an exemplary eyelid temperature profile of an innerand outer eyelid temperature versus time when heat is applied to theexterior of the eyelid;

FIG. 5 illustrates an exemplary eyelid lid temperature profile of insideand outside eyelid temperature versus time when heat is applied to theinside the eyelid;

FIG. 6 is a flowchart illustrating an exemplary process of applying heatto the inner eyelid relating to treating meibomian glands;

FIG. 7 illustrates an exemplary lid temperature profile of eyelidtemperature versus time when heat and force is applied to inside theeyelid;

FIG. 8 is a flowchart illustrating an exemplary process of applying heatto the inner eyelid with the addition of force applied to the outside orouter surface of the eyelid relating to treating the meibomian glands;

FIG. 9 illustrates a heat and force application device according to oneembodiment relating to the present invention to facilitate theapplication of heat to the inside and force to the outside of apatient's eyelid relating to treating meibomian glands;

FIG. 10 illustrates a lid warmer component of the heat and forceapplication device illustrated in FIG. 9, which is adapted to fit onto apatient's eye to controllably deliver heat to the inside of thepatient's eyelid, according to one embodiment relating to the presentinvention;

FIG. 11 illustrates the process of placing the lid warmer on thepatient's eye inside the eyelid to install the heat application deviceonto a patient's eye for treating the meibomian glands, according to oneembodiment relating to the present invention;

FIG. 12 illustrates a cross-sectional view of the lid warmer illustratedin FIGS. 9-11 to further illustrate heat delivery components andfeatures of the lid warmer, according to one embodiment relating to thepresent invention;

FIGS. 13A and 13B illustrate embodiments of a lid warmer and eyecup heatand force application device for securing the eyecup to the lid warmeras part of installing the force application device onto a patient's eyefor treating the meibomian glands;

FIG. 14 illustrates an interface adapted to be attached between theeyecup and the controller of FIGS. 9-13B for facilitating selective andcontrollable communication of heat and/or force to the eyelid, accordingto one embodiment of the present invention;

FIG. 15 illustrates a top level system diagram of the temperature andpressure control and communication components of the heat and forceapplication device for selectively and controllably communicating to thelid warmer and eyecup components to apply heat to the inside of apatient's eyelid and/or force to the outside of the patient's eyelid,according to one embodiment relating to the present invention;

FIG. 16 illustrates an interface circuit diagram for the heating andforce application device, according to one embodiment relating to thepresent invention;

FIG. 17 illustrates a pressure control system for the heating and forceapplication device to selectively and controllably apply force to theoutside of a patient's eyelid, according to one embodiment relating tothe present invention;

FIG. 18 illustrates a temperature control system for the heating andforce application device to selectively and controllably apply heat tothe inside of a patient's eyelid, according to one embodiment relatingto the present invention;

FIG. 19 is a flowchart illustrating the basic process employed by theheat and force application device to selectively and controllably applyheat to the inside of a patient's eyelid and/or force to the outside ofthe patient's eyelid, according to one embodiment relating to thepresent invention;

FIG. 20 illustrates a system state flow diagram for the heating andforce application device, according to one embodiment relating to thepresent invention;

FIGS. 21A and 21B illustrate the “Reset” state flow diagram according tothe system state flow diagram of FIG. 20, according to one embodimentrelating to the present invention;

FIG. 22 illustrates the optional “Fuseblow” state flow diagram accordingto the system state flow diagram of FIG. 20, according to one embodimentrelating to the present invention;

FIG. 23 illustrates the “Run” state flow diagram according to the systemstate flow diagram of FIG. 20, according to one embodiment relating tothe present invention;

FIG. 24 illustrates the “Pause” state flow diagram according to thesystem state flow diagram of FIG. 20, according to one embodimentrelating to the present invention;

FIGS. 25A and 25B illustrate the “Monitor” state flow diagram accordingto the system state flow diagram of FIG. 20, according to one embodimentrelating to the present invention;

FIG. 26 illustrates the “Stop” state flow diagram according to thesystem state flow diagram of FIG. 20, according to one embodimentrelating to the present invention;

FIG. 27 illustrates an exploded perspective view of an alternative heatand force application device for treating MGD, according to oneembodiment relating to the present invention;

FIG. 28 is an illustration of the alternative heat and force applicationdevice according to a cross section taken along line A-A in FIG. 27,according to one embodiment relating to the present invention;

FIG. 29 illustrates an exploded view of the alternative heat and forceapplication device according to FIG. 27, according to one embodimentrelating to the present invention;

FIG. 30 illustrates a sectional view of the alternative heat and forceapplication device according to FIG. 27, according to one embodimentrelating to the present invention;

FIGS. 31A and 3B are illustrations of another alternative heat and forceapplication device, according to one embodiment of the presentinvention;

FIG. 32 is an illustration of another alternative heat and forceapplication device, according to one embodiment of the presentinvention;

FIG. 33 is an illustration of another alternative heat and forceapplication device, according to one embodiment of the presentinvention;

FIG. 34 is an illustration of another alternative heat and forceapplication device, according to one embodiment of the presentinvention;

FIG. 35 is an illustration of another alternative heat and forceapplication device, according to one embodiment of the presentinvention;

FIGS. 36A and 36B are illustrations of another alternative heat andforce application device, according to one embodiment of the presentinvention;

FIG. 37 is an illustration of another alternative heat and forceapplication device, according to one embodiment of the presentinvention;

FIGS. 38A and 38B are illustrations of another alternative heat andforce application device, according to one embodiment of the presentinvention;

FIG. 39 is an illustration of another alternative heat and forceapplication device, according to one embodiment of the presentinvention;

FIG. 40 is an illustration of another alternative heat and forceapplication device, according to one embodiment of the presentinvention;

FIG. 41 is a flowchart illustrating an alternative meibomian glandtreatment employing applying heat and force to tissue proximate themeibomian gland to reduce heat loss when heat is applied to melt,loosen, or soften obstructions or occlusions;

FIG. 42 is a flowchart illustrating an alternate meibomian glandtreatment employing applying heat to the outside of a patient's eyelidand force to the inside of the patient's eyelid for treating meibomianglands;

FIG. 43 is a flowchart illustrating an alternate meibomian glandtreatment employing applying heat and force to the outside of apatient's eyelid for treating meibomian glands; and

FIG. 44 is a flowchart illustrating an alternate meibomian glandtreatment employing applying heat to both the inside and the outside ofa patient's eyelid for treating meibomian glands.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The embodiments set forth below represent the necessary information toenable those skilled in the art to practice the invention and illustratethe best mode of practicing the invention. Upon reading the followingdescription in light of the accompanying drawing figures, those skilledin the art will understand the concepts of the invention and willrecognize applications of these concepts not particularly addressedherein. It should be understood that these concepts and applicationsfall within the scope of the disclosure and the accompanying claims.

One embodiment of the present invention includes the breakthrough andpreviously unknown method of applying heat to the inner surface of theeyelid to treat dry eye caused by meibomian gland dysfunction (MGD).Applying heat to the inside of the eyelid can effectively andefficiently raise the temperature at the meibomian glands to atemperature sufficient to melt, loosen, or soften more seriousocclusions or obstructions in the meibomian glands. The occlusions orobstructions can then be physically expressed to improve sebum flow fromthe meibomian glands to reduce evaporation of the aqueous layer.

Some patients have obstructions or occlusions in their meibomian glandsthat will not sufficiently melt, loosen, or soften to be expressedwithout attaining heightened temperatures at the meibomian glands. Inmany instances, these temperatures either cannot be achieved whenapplying heat to the outside of the eyelid, or these temperatures may beachievable, but only after applying heat to the outside of the eyelidfor a significant period of time. Heightened temperatures may only beachieved by applying heat at unsafe temperatures that would eitherproduce an unacceptable pain response to the patient or damage to thepatient's eyelid. This is because of the temperature drop between theoutside of the eyelid and the meibomian glands due to conductive heatloss. Heat applied to the outside of the eyelid must conductively travelthrough the eyelid tissue and through the tarsal plate that encases themeibomian glands inside the eyelid. As an example, it may take twenty tothirty minutes for the temperature at the meibomian glands to reach onlya temperature of 41 to 42 degrees Celsius when applying heat to theoutside of the eyelid that will not burn or damage the patient's eyelidor surrounding tissue. Temperatures may need to reach between 43 to 45degrees Celsius, for example, for melting, loosening, or softening ofcertain obstructions or occlusions in a patient's meibomian glands.

Until the present application, it was only known to apply heat to theoutside of the eyelid to treat meibomian gland dysfunction (MGD).Medical professionals would have thought it counterintuitive to applyheat to the inside of the eyelid. It was thought that applying heat tothe inside of the eyelid would risk damage to the eyelid or the eyeballitself. Previous studies of heat application to skin showed that damagecould occur for temperatures at or above 45 degrees Celsius. Thesestudies were made on external keratinized skin. The tissue on the innereyelids is non-keratinized epithelium, and as such, is not as wellprotected from heat as keratinized skin. Thus, one would naturallybelieve that applying heat to the inside of the eyelid would produce apain response at lower temperatures than on the outer eyelid surface.However, it has been surprisingly discovered that applying heat to theinside of the eyelid is not only safe, but effective at dislodgingobstructions and/or occlusions in the meibomian glands as part of a MGDtreatment.

It was hypothesized that heating the inside of the eyelids may provide amore efficient conductive heat transfer to the meibomian glands.Attaining a more efficient heat transfer may allow higher temperaturesto be attained at the meibomian glands and in a more efficient time tomelt, loosen, or soften more serious obstructions or occlusions in themeibomian glands. The meibomian glands are located closer to the insidesurface of the eyelid than the outside surface of the eyelid. Further,there is no tarsal plate located between the inside of the eyelid andthe meibomian glands. Thus, it was discovered than conductive heattransfer to the meibomian glands is more efficient when heating theinside of the eyelid. Heat conduction increases with thinner tissue.

In this regard, an experiment was carried out where heat was applied tothe inside of the eyelid (and more particularly the palpebralconjunctiva) against traditional notions and known principles. It wasdiscovered that heat could be applied to the inside of the eyelidwithout damaging the patient's eye if regulated. For example, it wasdetermined that most patients can tolerate a surface temperature of43-44.5 degrees Celsius without anesthesia and without significant pain.It was found that some patients could tolerate temperatures over 44.5degrees Celsius without anesthesia. Further, it was discovered thanheightened temperatures could be attained and in less time when applyingheat to the inside of the eyelid than to the outside of the eyelid dueto more effective conductive heat transfer and the proximity to theheating device.

An exemplary lid temperature profile 32 that may be generated when heatis applied to the inside of the eyelid is illustrated in FIG. 5. There,a graph depicts what the temperature of the inner surface of an eyelidmay be as a function of time when a source of constant heat is appliedto an example subject patient. A heat source attached to the inside ofthe patient's eyelid is turned on for a period of time. For thispatient, it took approximately 30 seconds for the eyelid's inner surfaceto reach about 44 degrees Celsius. Unlike the lid temperature profileillustrated in FIG. 4, the inner surface of the patient's eyelid didreach a higher temperature when heat was applied to the inside of theeyelid. For example, it may only take two to three minutes to bring thetemperature at the meibomian glands to 43-45 degrees Celsius or higherwhen applying heat to the inside of the eyelid. While not limiting tothe present invention, the ability to raise the temperature at themeibomian glands may prove instrumental in melting, loosening, orsoftening obstructions or occlusions in the meibomian gland to reach theloosening, softening, or melting point of the obstruction or occlusion.

In this regard, an embodiment of the present invention to apply heat tothe inside or inner surface of the eyelid proximate the meibomian glandsto treat MGD in basic form is illustrated in the flowchart of FIG. 6.This has the advantage in that it typically takes less time to raise thetemperature at the meibomian glands sufficient to melt, loosen, orsoften an obstruction or occlusion than if heat were applied directly tothe outside of the eyelid. Further, heating the inside of the eyelid mayallow higher temperatures to be achieved than if the outside of theeyelid were heated.

First, heat is applied to the inner surface of the eyelid to atemperature adequate to melt, loosen, or soften obstructions orocclusions in the meibomian glands (step 40). For example, heat may beapplied to raise the temperature at the inside of the eyelid to 43-47degrees Celsius, although the present invention is not limited to thistemperature range. A time range to apply heat may be a period between1-10 minutes, and may be limited to a range of 3-6 minutes. The heat maybe regulated meaning that a heating means or element is controlled to bewithin the temperatures and means that are safe for the inner surface ofthe eyelid and at a sufficient temperature for melting, loosening, orsoftening an occlusion or obstruction in the meibomian gland. Bysufficient temperature, this refers to the amount of heating needed toheat the palpebral conjunctiva to achieve the desired melting,loosening, or softening of the obstruction. The heat may be maintainedfor a period of time until the temperature reaches the desired levelsufficient to melt, loosen, or soften the obstructions or occlusions(step 42). For example, the heat may be applied for 1 to 10 minutes,although the present invention is not limited to any particular amountof heat application time. Thereafter, either during heating or after,obstructions or occlusions in the meibomian glands may be expressed sothat sebum flow is restored from the glands to establish a sufficientlipid layer (step 44).

While not limiting to the present invention, the ability to effectivelyand more efficiently raise the temperature at the meibomian glands mayprove instrumental in melting, loosening, or softening obstructions orocclusions in the meibomian gland to reach the loosening or meltingpoint of the obstruction or occlusion.

As used herein, the terms “melt,” “loosen,” and “soften” and variantsthereof are to be interpreted broadly. These terms broadly encompass anychange in form or state of the obstructive or occluding material causingor contributing to an obstruction or occlusion related to a disorder ofthe eye or eyelid structure to a form such that the obstruction orocclusion can be more easily freed or expressed. This includes, but isnot limited to, changing form from less of a solid form or state to moreof a liquefied form or state, including but not limited to dissolving,loosening, liquefying, and/or softening of the obstructive or occludingmaterial to be removed, and/or dissolving, loosening, liquefying, orsoftening of material that holds together particulate matters causing orcontributing towards the obstruction or occlusion related to a disorderof the eye or eyelid structure and other modalities.

The application of heat may be regulated, meaning that a heating meansor element is controlled to be within the temperatures and means thatare safe for the inner surface of the eyelid and at a sufficienttemperature for melting, loosening, or softening an occlusion orobstruction in the meibomian gland. The heat is maintained for a periodof time sufficient to melt, loosen, or soften the occlusions orobstructions. Either during heat application or after heat applicationis removed, the occlusions or obstructions in the meibomian glands areexpressed to remove obstructions or occlusions thus providing animproved pathway to restore or improve sebum flow from the gland.

In one embodiment, increasing the temperature of the surface of thepalpebral conjunctiva to at least 37 degrees Celsius can begin toprovide therapeutic effect for milder cases of MGD. A therapeutictemperature can be any temperature above body temperature. One preferredrange for treatment is 43 to 45 degrees Celsius, with a target of 43 to44.5 degrees Celsius. A time range to apply heat may be a period between1-10 minutes, and may be limited to a range of 3-6 minutes. Temperaturein this range has been found effective and comfortable to the patientwhen treating MGD.

In one embodiment, the application of heat may be regulated. Regulatedheat can include controlling heat according to a temperature profile.The temperature profile may be a constant temperature, include ramp-ups,ramp-downs, peaks and valleys. Further, the temperature profile mayinclude heat pulses or be modulated with various characteristics,including the use of on/off switching or pulse width modulation (PWM)techniques for example. The use of modulated heat may allow thetemperature to be raised even higher at the eyelid without damages tothe patient's eyelid since the increased temperatures are applied forshorter periods of time. Obstructions or occlusions in the meibomianglands may have melting, loosening, or softening points that are beyondtemperatures that may be applied without the use of modulated heat. Thetemperature needed to melt, loosen, or soften obstructions or occlusionsmay depend on how keratinized the obstruction or occlusion is. Not allobstructions or occlusions have the same melting, loosening, orsoftening points.

By example only, elevated temperatures between 45 and 55 degrees Celsiusmay be possible when applying regulated heat, especially if the eyelidhas been anesthetized. However, heat must always be applied to theeyelid at temperatures that take into consideration the pain response ofthe patient as well as whether damage will occur to the patient's eyelidand/or surrounding tissues. Depending on the severity of the patient'sMGD or the patient's pain tolerance, elevated temperatures may be usedwith patient's on an individualized basis when applying heat. It hasbeen found that lighter skinned patients can generally tolerate lessheat than darker skinned patients, and darker skinned patients tend toexhibit less inflammation as a result of exposure to the heat. Otherfactors, including humidity, may contribute to a patient's tolerate togreater temperatures. For example, humans can generally tolerate heat upto 70 to 80 degrees Celsius in dry saunas where humidity is low.Application of heat in higher humidity environments may cause painand/or burns to occur at lower temperatures.

Severe cases of MGD that cause substantial irritation or risk to thepatient may even call for temperatures that would produce category oneor two burns to the patient's eyelid, since these burns generally heal.Temperatures that cause category three burns should be avoided. Insummary, treatment times and/or temperature can be adjusted to accountfor these differences. The present invention is not limited to anyparticular temperature or time ranges as long as therapeutic temperatureis being applied.

The regulated heat can be maintained at a therapeutic temperature for atreatment period. The treatment period can be approximately 1 to 10minutes for example. The heat could also be repeatedly applied andmaintained for a desired period of time to keep the occlusion orobstruction in a melted, loosened, or softened state. Either during orafter such treatment by regulated heat, mechanical expression of lipidsand other fluids from the meibomian glands has been found to clearobstructions which have essentially melted or been placed in asuspension state (by virtue of melting materials binding solidstogether).

Optionally, after expression of the occlusions or obstructions isperformed (step 44), an optional pharmacological agent may be applied tothe meibomian gland to promote the free flow of sebum and/or reduce orprevent inflammation or infections of the eye or eyelids (step 46). Manypharmacological agents have been proposed for treatment of dry eyesyndrome, any of which may be effective or more effective upon clearingof obstructions within the meibomian glands. Some of the pharmacologicalagents that may be utilized include, but are not limited to: antibioticssuch as topical or oral tetracycline and chemically modifiedtetracycline, testosterone, topical or oral corticosteroids, topicalandrogens or androgen analogues, omega 3 fatty acid compounds such asfish oils, Laennec, enzymes that promote lipid production, agents thatstimulate production of enzymes that promote lipid production, and/orany agent which acts as a secretagogue to enhance meibomian glandsecretion or secretion of other tear components. For example, androgenand androgen analogues and TGF-beta have been reported to act as asecretagogue to enhance meibomian gland secretion. These compounds areillustrative examples of appropriate pharmacological agents, but thoseskilled in the art will appreciate that other pharmacological compoundsmay be utilized.

Also, agents, such as Restasis (cyclosporine A), that replace or promoteproduction of the tear component may also be applied more effectivelyafter treating the meibomian glands according to the present invention.Treating the meibomian glands improves the lipid layer, thus reducingevaporation and conserving the aqueous layer. Conservation of theaqueous layer reduces the need for tear substitutes to be appliedthrough tear component agents. Thus, tear component agents may not haveto be used as often when employing the present invention to treat apatient's MGD.

In the course of experimenting with the application of heat to theinside of the eyelid, it was also discovered that convective heat lossesoccur due to blood flow in the blood vessels located inside the eyelid.Blood flow through blood vessels located inside the eyelid producesconvective heat losses. The blood flow serves as a natural “heat sink”provided by the body. Convective heat loss is lessened when applyingheat to the inside of the eyelid than when applying heat to the outsideof the eyelid. This is because fewer blood vessels are located betweenthe meibomian glands and the inside of the eyelid than the outside ofthe eyelid. The meibomian glands are located closer to the inside of theeyelid. However, convective heat loss still occurs when heating theinside of the eyelid. However, if the blood flow were reduced,convective heat losses could be minimized allowing for temperatures tobe attained and sustained at the meibomian glands in an even moreefficient manner and in less time.

In this regard, an exemplary lid temperature profile 50 when heat isapplied to the inside of the eyelid and force at various pressure levelsis applied to the outside of the eyelid is illustrated in FIG. 7. There,a graph depicts the temperature at the inner and outer surface of aneyelid as a function of time when a source of constant heat and pressureis applied to an example subject patient. Initially, no heat or pressureis applied to the eyelid. In this example, the temperature at the insideof the eyelid is approximately 36 degrees Celsius while the temperatureat the outside of the eyelid is approximately 35 degrees Celsius. Whenthe heat source is turned on to apply heat to the inside of the eyelidand a 70 mm Hg pressure is applied to the outside of the eyelid, thetemperature at the inside of the eyelid dramatically increases quickly.The pressure being applied to the eyelid is reducing blood flow in theeyelid, which reduces convective heat loss and increases conductive heatgain. The temperature at the outside of the eyelid increases quickly aswell, but less dramatically than at the inside of the eyelid since theheat source is at the inside of the eyelid. A nominal temperature ofapproximately 40.5 and 38.3 degrees Celsius is reached at the inside andoutside of the eyelid, respectively.

If the pressure is increased, even higher temperatures are attained asillustrated in FIG. 4. Finally, when the heat source is completely shutoff, the temperature degrades. However, the temperature at the eyeliddoes not degrade immediately due to the force continuing to be applied.Again, the force reduces blood flow to prevent convective heat loss. Ifboth heat and force are shut off after being applied, the temperature atthe eyelid does degrade more rapidly. This is because blood flow in theeyelid is unobstructed, allowing the body's blow flow to “quicklyconvect the heat away. Thus, the lid temperature profile 50 of FIG. 7illustrates temperature at the eyelid can be increased effectively andquickly with the application of force in addition to heat. Note that theapplication of force to reduce convective heat loss can be appliedwhether heat is applied to the inside or outside of the eyelid. Asillustrated in FIG. 7, the application of force is effective in bothscenarios.

Thus, one embodiment of the present invention also includes the furtherapplication of force to the patient's eyelid in addition to heat. Theapplication of force can further assist in obtaining higher temperaturesmore efficiently inside the eyelid at the palpebral conjunctiva and atthe meibomian gland in a shorter period of time and thus moreefficiently. This is because the application of force may reduce bloodflow to the eyelid to reduce convective heat loss, as discussed above.

In this regard, an embodiment of the present invention to apply heat andforce to the eyelid to treat MGD is illustrated in the flowchart of FIG.8. First, heat is applied to the eyelid to raise the temperature at themeibomian glands to the desired level (step 60). For example, heat maybe applied to raise the temperature at the inside of the eyelid to 44-47degrees Celsius. The heat may be applied to the inside or outside of theeyelid, or both sides of the eyelid. The heat may also be regulated,meaning that a heating means or element is controlled to be within thetemperatures and means that are safe for the eyelid and at a sufficienttemperature for melting, loosening, or softening an occlusion orobstruction in the meibomian gland. A force is also applied to theeyelid to reduce blood flow in the eyelid to allow the applied heat tomore quickly raise the temperature at the meibomian glands (step 62).The force may be applied to the inside or outside of the eyelid.

The heat and/or force may be maintained for a period of time sufficientto raise the temperature at the meibomian glands sufficient to melt,loosen, or soften the obstructions or occlusions (step 64). The forcemay be maintained after heat is removed, or vice versa depending on thetreatment technique desired. Maintaining force after heat is removed maycause the temperature at the meibomian glands to dissipate more slowlythan if force is removed. Maintaining heat without maintaining force maybe employed to allow blood flow in the eyelids, such as betweensuccessive treatments. For example, it may be desirable to maintain heatto lessen the total amount of treatment time while applying and removingforce between treatments. Also, it may not be necessary to applysignificant amounts of force or for the same duration as heat if theobstruction or occlusion is located in close proximity to the lid marginrather than in the deeper portions of the meibomian gland.

Applying force can also result in a more efficient conductive heattransfer from an applied heat source, because the pressure created bythe force causes the heat source to be compressed against the tissue ofthe eyelid. This compression can have several benefits. Compressionspreads out the tissue to which heating is applied thus making itthinner and improving conductive heat transfer. Compression can also“squeeze out” air pockets at the surface of the eyelid due to themicroscopic roughness of skin. Thus, compression of the heat sourceagainst the eyelid increases the surface contact between the heat sourceand the surface of the eyelid (which increases the heat transferequation) to provide a more effective conductive heat transfer to themeibomian glands. This results in the meibomian glands being heated tothe desired temperature level in a shorter period of time due to thesegained efficiencies. Further, increased temperatures may be attainedthat may not have otherwise been obtained, or obtained using less heator thermal energy. Because the heating is located in close proximity tothe eyelid surface and heating is further compressed against the eyelidsurface, heat transfer is very efficient providing for the temperatureat the surface of the eyelid to be very close to the temperature at themeiboimian glands.

Further, note that while the exact reduction in times to heat themeibomian glands will vary from patient to patient when force isapplied, and may be based on the amount of pressure applied to thepatient's eyelid, in general, the change in heating times can vary by asmuch as several hundred percent, for example, when compared to previousmethods. As an example, this can translate into five (5) or more minutesthat one has to expel an obstruction or occlusion before suchre-solidifies when compared with prior methods.

The force may be regulated, meaning that a force generating means iscontrolled to be within the pressure ranges that are safe to be appliedto the eyelid and at sufficient pressure to allow the temperature at themeibomian gland to be raised sufficiently. The force can also be aconstant force and be provided manually. For example, force may beprovided by a technician or doctor's finger or thumb as heat is applied.The force may be applied during heating, after heating, or both duringand after heating. In either case, the force may assist in expressingocclusions or obstructions when in a loosened, softened, or melted statefrom the meibomian glands. The force may include vibratory type forces,including those generated mechanically or those using fluid type devicesor mechanisms. The force can be applied at a particular location orvector of the patient's eyelid to be specifically directed to themeibomian glands. This may reduce the level of force needed to expressobstructions or occlusions in the glands. The level of force needed toexpress obstructions or occlusions in the glands may also be greatlyreduced when heat is applied to the obstructions or occlusions to placethem in a melted, softened, or loosened state.

The application of force can also stimulate the movement of fluids orsuspensions of occlusions or obstructions from the glands. The presentinvention can be used with devices which generally apply a regulatedforce or milking action to the eyelid to express the fluids orsuspensions or to otherwise mechanically stimulate the movement offluids from the glands. In some instances, a small, gentle, continuousforce applied to the eyelid will assist in expression of the fluids andsuspensions. Vibration can also be used when applying forcesimultaneously or immediately after the heating to further assist in theexpression.

Thereafter, either during heating and/or the application of force orafter either, obstructions or occlusions in the meibomian glands may beexpressed so that sebum flow is restored from the glands to establish asufficient lipid layer (step 66).

Just as discussed above in the flowchart of FIG. 6 where only heat isapplied, the application of heat may be regulated. Regulated heat caninclude controlling heat according to a temperature profile. Thetemperature profile may be a constant temperature, include ramp-ups,ramp-downs, peaks and valleys. Further, the temperature profile mayinclude heat pulses or be modulated with various characteristics,including the use of on/off switching or pulse width modulation (PWM)techniques for example. The use of modulated heat may allow thetemperature to be raised even higher at the eyelid without damages tothe patient's eyelid since the increased temperatures are applied forshorter periods of time. Obstructions or occlusions in the meibomianglands may have melting, loosening, or softening points that are beyondtemperatures that may be applied without the use of modulated heat. Thetemperature needed to melt, loosen, or soften obstructions or occlusionsmay depend on how keratinized the obstruction or occlusion is. Not allobstructions or occlusions have the same melting, loosening, orsoftening points.

By example only, elevated temperatures between 45 and 55 degrees Celsiusmay be possible when applying regulated heat, especially if the eyelidhas been anesthetized. However, heat must always be applied to theeyelid at temperatures that take into consideration the pain response ofthe patient as well as whether damage will occur to the patient's eyelidand/or surrounding tissues. Depending on the severity of the patient'sMGD or the patient's pain tolerance, elevated temperatures may be usedwith patient's on an individualized basis when applying heat. It hasbeen found that lighter skinned patients can generally tolerate lessheat than darker skinned patients, and darker skinned patients tend toexhibit less inflammation as a result of exposure to the heat. Otherfactors, including humidity, may contribute to a patient's toleranc ofgreater temperatures. For example, humans can generally tolerate heat upto 70 to 80 degrees Celsius in dry saunas where humidity is low.Application of heat in higher humidity environments may cause painand/or burns to occur at lower temperatures.

Severe cases of MGD that cause substantial irritation or risk to thepatient may even call for temperatures that would produce category oneor two burns to the patient's eyelid, since these burns generally heal.Temperatures that cause category three burns should be avoided. Insummary, treatment times and/or temperature can be adjusted to accountfor these differences. The present invention is not limited to anyparticular temperature or time ranges as long as therapeutic temperatureis being applied.

The regulated heat can be maintained at a therapeutic temperature for atreatment period. The treatment period can be approximately 1 to 10minutes for example. The heat could also be repeatedly applied andmaintained for a desired period of time to keep the occlusion orobstruction in a melted, loosened, or softened state. Either during orafter such treatment by regulated heat, mechanical expression of lipidsand other fluids from the meibomian glands has been found to clearobstructions which have essentially melted or been placed in asuspension state (by virtue of melting materials binding solidstogether).

Optionally, after expression of the occlusions or obstructions isperformed (step 66), an optional pharmacological agent may be applied tothe meibomian gland to promote the free flow of sebum and/or reduce orprevent inflammation or infections of the eye or eyelids (step 68). Thediscussion regarding use of pharmacological agents above for theflowchart in FIG. 6 is equally applicable for this embodiment and thuswill not be repeated here. Those compounds are illustrative examples ofappropriate pharmacological agents, but those skilled in the art willappreciate that other pharmacological compounds may be utilized.

In one embodiment, a force can be applied to the outside of the eyelidwhile heat is applied to the inside of the eyelid to treat MGD. Theheating of the inner surface of the upper or lower eyelid can be done byany convenient method. The lids can be heated one at a time or both atonce, depending on the time available to remove the occlusions onceheated. One device for heating the palpebral conjunctiva is illustratedin FIGS. 9-14.

FIG. 9 illustrates the overall device referred to as a heat and forceapplication device 70. In this embodiment, the heat and forceapplication device 70 consists of a hand-held, battery-operatedcontroller 72 that contains heat and pressure generating and regulationcomponents. The controller 72 can also be a non hand-held device that iseither mounted or rests on a table top, for example. The controller 72as described herein is intended to describe and encompass any device,including but not limited to electronic and pneumatic controls andsupporting components, that is adapted to allow and control theapplication of heat and/or force to the patient's eyelid. The controller72 is connected to a disposable component 74, via a controller interface76, to generate heat and force at an eyelid 78, as illustrated in FIG.9. The disposable component 74 consists of a lid warmer 90 provided inthe form of a lens (illustrated in FIGS. 10-12) that applies heat to theinside of the patent's eyelid and interfaces with an eye cup to applyforce to the outside of the patient's eyelid (illustrated in FIGS.13-14). Both can be used in concert to treat MGD for a single eye. Theinterface 76 tubing can be wrapped around the patient's ear 77 with anyexcess clipped to the patient's clothing. The heat and force applicationdevice 70 is intended for use by physicians to apply localized heat andpressure therapy for treating MGD.

The controller 72 contains a user interface 80 to allow a physician orother technician to control the heat and force application device 70.Temperature and pressure being applied to the patient's eyelid 78 can beseen on a temperature display 82 and a pressure display 84. By observingtemperature and pressure displays 82, 84, the physician can determinewhen a therapeutic temperature and pressure have been reached. Forexample, the temperature and pressure displays 82, 84 may be segment bargraphs so that both the temperature and pressure levels and theincreasing or decreasing nature of the temperature and pressure levelscan be seen. The temperature level to be reached at the patient's eyelidcan either be set to a static level within the controller 72, orcontrollable by a physician or technician. The force and thus thepressure applied to the patient's eyelid is controllable by squeezing aforce lever 86. When a physician or technician desires to apply force,the force lever 86 can be squeezed. To release force and thus reducepressure, the force lever 86 is disengaged. The pressure created by theforce applied to the patient's eyelid is displayed on the pressuredisplay 84.

A timer display 88 can be provided on the controller 72 to display theamount of time that heat and/or force has been applied to the patient'seyelid 78. The timer display 88 can display a cumulative amount of timepassed or provide a countdown timer if an initial duration is set. Forexample, the timer display 88 may be comprised of a number of sevensegment displays. In one embodiment, the timer display 88 will countdown from one hundred eighty (180) seconds and will flash at one hundredtwenty (120) seconds and sixty (60) seconds, which is an indicator tothe physician to release the force lever 86 and then reapply force andpressure by squeezing the lever 86 again.

FIG. 10 illustrates the disposable component 74 in more detail. Thedisposable component 74 consists of a lid warmer 90 that includes a lensin the disclosed embodiment. The lens 90 contains a heating element toapply heat to a patient's eyelids 91A, 91B, but also provides aninsulating back plate against which force may be applied. As illustratedin FIG. 11, the lens 90 is placed on the patient's eye with thepatient's upper and lower eyelids 91A, 91B resting on the outsidesurface of the lens 92. Before installation, the scleral side of lens 90may be lubricated with saline, or equivalent lubricating drops. The lens90 is then inserted onto the patient's eye under the eyelids 91A, 91B. Aheating element (not shown) is contained within the lens 90 that canapply heat to the inside of the patient's eyelid when installed. Thematerial used to construct the lens 90 is not electrically conductive,but is thermally conductive to allow heat from the heating elementinside to be transferred to the patient's eyelid. The lens 90 can beconstructed out of a plastic, including a clear plastic such as LEXANHPS2 for example. Further, the lens 90 can be constructed from abiocompatible material, such as polymethylmethacrylate (PMMA), epoxy, orother materials well known to those skilled in the art. The lens 90 maybe flexible, but ideally should be only minimally compressible to fitagainst the patient's eyeball.

The lens 90 also contains a lid warmer platform or tab 94 that isattached to the lens 90. The lid warmer platform 94 may be connectedperpendicularly to the lens 90 such that it extends away from thepatient's eye when installed. The lid warmer platform 94 providesseveral benefits. First, provides a handle for insertion and movement oradjustment of the lens 90 and its heating element. Second, it provides aguide post for a compression force device to attach to apply a force tothe patient's eyelid while the lens 90 applies heat to the inside of thepatient's eyelid. It can also support a lens electrical interface 96 toallow the lens 90 to electrically connect the heating element inside thelens 90 to the controller 72 via the interface 76. The controller 72 canthen apply electrical energy to the heating element to generate heatwithin the lens 90 and thus to the inside of the patient's eyelid wheninstalled. Second, it provides a support structure for interfacecircuitry 98. The interface circuitry 98 provides electrical connectionsfor energizing the heating element and communicating temperaturemeasured at the lens 90 back to the controller 72 for heat regulation.The interface circuitry 98 will discussed later in this application andin regard to FIG. 16.

FIG. 12 illustrates a cross-sectional view of the lid warmer employingthe lens 90 illustrated in FIGS. 9-11 to further illustrate heatdelivery components and features of the lid warmer, according to oneembodiment of the present invention. The lens 90 is formed by a scleralside 93 being attached to an eyelid side 92. The scleral side 93 of thelens 90 contains a bend 100 around its circumference edge to provide anattachment edge 102 to support attachment of the eyelid side 92. Becauseof the bend 100, a hollow chamber 104 is formed inside the lens 90. Thehollow chamber 104 supports a heating element 106 contained inside thelens 90 to generate heat when energized. The heating element 106 abutsagainst the eyelid side 92 of the lens 90 so that the heat generated islocated adjacent the inner eyelid to apply heat to the meibomian glands.The heating element 106 is attached to the interface circuitry 98 via afused link 108, which is then attached to the controller 72 via the lidwarmer platform 94 being attached to the controller interface 76. Inthis manner, the controller 72 can cause the heating element 106 insidethe lens 90 to generate heat by applying an electrical signal to theinterface circuitry 98 which is connected to the heating element 106. Ifthe temperature exceeds the threshold temperature level of the fusedlink 108, the link 108 would melt and create an open circuit to disablethe heating element 106 for safety reasons. Alternatively, the fusedlink 108 could be a thermal link provided as an integrated part of theheating element such that the fused link 108 would melt and create anopen circuit at a given threshold temperature.

The heating element 106 may be provided in any form or material. Theheating element 106 may be a resistive type heater, a thick film heater,or any one of a number of other types, such as a “flex circuit” (etchedmetal on flexible substrate) well known to those skilled in the art. Theheating element 106 can be formed to the shape of the lens 90. In theillustrated example, the heating element 106 is a material that is bothelectrically and thermally conductive. This may be important. Theelectrical conductivity characteristic allows current to be applied tothe heating element 106 to generate resistive heat. The thermalconductivity characteristic serves to evenly distributes the resistiveheat over the entire heating element 106 to more evenly distribute theheat to the patient's eyelid. Without these characteristics, it may bemore difficult to regulate heat generated by the heating element toefficiently and effectively melt, loosen, or soften obstructions orocclusions in the meibomian glands. Examples include the E5101carbon-loaded polyphenylene sulfide and the E2 liquid crystal polymer,both manufactured by Cool Polymers, Inc.

The size of the lens 90 may also play a part in the heating element 106selection and the amount of heat it must generate to be effective in MGDtreatment. The lens 90 distributes heat generated by the heating element106. A larger lens 90 may distribute the heat generated by the heatingelement 106 more uniformly and over a larger surface area. Also notethat the application of heat to the patient's eyelid does notnecessarily have to include an embedded heating element 106 in the lens90. Heat application may be provided as part of the environment, such asair for example. The amount of heat applied, the temperature reached atthe meibomian glands as a result, where the heat is applied on thepatient's eyelid or surrounding tissue, and the duration of heat appliedcan control the selection of the heating source.

In addition to the insulation provided by the material used to constructthe lens 90, the lens 90 may also contain an integrated insulator insidethe chamber 104 as an additional measure of insulation. Insulationprevents substantial heat from reaching the eyeball and thus protectsthe cornea and sclera. As employed herein, the term “insulate” or“insulation” is intended to include any component or material and/orspecific geometries of components or materials, wherein there is greaterresistance to thermal conduction or radiation towards the surface of theeye than towards the eyelid. Stated alternatively, in the insulatorthermal energy radiates more easily towards the eyelid 91A, 91B thantowards the eyeball surface in order to minimize the possibility ofcausing injury to the eyeball. In the lens 90 example of FIG. 12, theintegrated insulator is air and is formed by the natural gap that existsby the space left by the heating element 106 not filling up the entirevolume of the chamber 104. The heating element 106 is biased accordingto its location in the lens 90, and in particular to be located behindthe integrated insulator, to produce more heat on the insides of thepatient's eyelid than on their eyeball.

FIG. 13A illustrates an eyecup 110 that is adapted to allow thecontroller 72 to apply a force to the patient's eyelids 91A, 91B inaddition to heat. The eyecup 110 is acurved carrier 112 that supports aninflatable bladder 114. The inflatable bladder 114 is attached to thecurved carrier 112. The inflatable bladder 114 is then connected to thecontroller 72 via a tubing 118 in the controller interface 76 (see FIG.14) such that the controller 72 can pump air into the tubing 118 toinflate the inflatable bladder 114. When inflated, the eyecup 110applies force to the outside of the eyelid 91A, 91B while heat can beapplied via the lens 90 and heating element 106. To apply force to thepatient's eyelids 91A, 91B, the bladder 114 is inflated under control ofthe controller 72. To release the force and thus reduce pressure, theair in the bladder 114 is released by the controller 72.

When desired to be used, the lid warmer platform 94 is inserted into aneyecup orifice or slot 113 in the eyecup 110 between a latchingmechanism 116. The latching mechanism 116 provides a means to secure thelid warmer platform 94 to the eyecup 110 when in use as well as providean interface to electrically connect the lid warmer electrical interface96 to the controller 72 via the controller interface 76. The latchingmechanism 116 is comprised of a carrier 117 having a semi-circularcarrier base 119. The carrier base 119 receives an eyecup platform 121attached to the eyecup 110. The carrier base 119 and eyecup platform 121can be squeezed together like a clip to control an opening through whichthe lid warmer platform 94 is inserted into the carrier 117 wheninserted into the orifice 113 of the eyecup 110. When the carrier base119 is not squeezed against the eyecup platform 121, the carrier openingthrough which the lid warmer platform 94 is inserted closes to securethe lid warmer platform 94 to the carrier 117, and thus the eyecup 110.The eyecup platform 119 is adapted to allow the lid warmer platform 94to rest on top when inserted into the eyecup orifice 113. When inserted,the electrical interface 96 of the lid warmer 74 contacts a carrierinterface 123, which provides an electrical connection between theelectrical interface 96 and the controller interface 76.

FIG. 13B illustrates an alternative latching mechanism 116A to oneillustrated in FIG. 13A. The latching mechanism 116 is compressed in thehorizontal plane while the eyecup 110 is moved forward along the lidwarmer tab 94 until it rests against the outside of the patient'seyelids 91A, 91B. When the latching mechanism 116 is released, theeyecup 110 is fixed in place in its location along the lid warmer tab94. In this manner, the patient's eyelids 91A, 91B are “sandwiched”between the lens 90 and the eyecup 110. More information and detailregarding the latching mechanism 116 is illustrated in FIGS. 27-30 andwill be described later in this application.

FIG. 14 illustrates more detail regarding the controller interface 76.The controller interface 76 couples the controller 72 to the lens 90 andeyecup 110 to allow the controller 72 to controllably apply heat and/orforce to the patient's eyelid as part of a MGD treatment. The controllerinterface 76 contains a connector 120 on one end that connects to thecontroller 72. The connector 120 includes both an electrical interface122 and a pneumatic interface 124. The electrical interface 122 allowsthe controller 72 to send and receive electrical signals over anelectronics wiring 126 to and from the lid warmer 90, as will bedescribed in more detail below. The electronics wiring 126 interfaceswith an eyecup electrical connector 128 on the eyecup 110 such that thelid warmer electrical interface 96 of the lid warmer 90 is connected tothe electronics wiring 126 when the lid warmer platform 94 is insertedinto the eyecup 110, as illustrated in the examples of FIGS. 13A and13B. The pneumatic interface 124 allows the controller 72 to pump intothe tubing 118 to inflate the inflatable bladder 114 on the eyecup 110to apply force to the patient's eye and to deflate the air in theinflatable bladder 114 to release force and relieve pressure. In theillustrated embodiment, the pneumatic interface 124 is securely coupledto the inflatable bladder 114 on the eyecup 110.

FIG. 15 supplements FIG. 14 to illustrate the interface componentsbetween the controller 72 and the disposable component 74 and the eyecup110, at a system level. The controller 72 of the heat and forceapplication device 70 contains a pressure control system 130 and atemperature control system 132. The pressure control system 130 is thecontrol component within the controller 72 that controls the pressurefrom the force applied to the patient's eye via the eyecup 110. Thetemperature control system 132 is the control component within thecontroller 72 that controls the heat applied to the patient's eye viathe lid warmer 90. The pressure control system 130 also communicates thepressure in the tubing 118 to a pressure sensor 134 within the pressurecontrol system 130. The pressure sensor 134 is used to determine thepressure level in the tubing 118 to display the pressure on the pressuredisplay 84 as well as to provide feedback to the controller 72 toprovide the various functions and controls for the system, as will bedescribed in more detail below. The pressure sensor 134 also allows therecordation of pressure data to be recorded by the controller 72, or anexternal data acquisition device (not shown) coupled to the controller72, if desired.

FIG. 15 also illustrates more detail regarding the latching mechanism116 on the eyecup 90. The latching mechanism 116A facilitates providinga connection between the lid warmer 90 and the lid warmer platform 94and the eyecup 110, and the lid warmer 90 to the electronics wiring 126when the eyecup orifice 113 is slipped over to the lens platform 94 tosecure the eyecup 110 to the patient's eyelid. Two different types oflatching mechanism 116, 116A were previously illustrated in FIGS. 13Aand 13B, either of which can be used to secure the platform 94 to theeyecup 110, or any other type may be used.

FIG. 16 illustrates the specific wiring and supporting circuitry thatcomprises the electronics wiring 126 to interface the controller 72, andparticularly the temperature control system 132, to the lid warmer 90 toapply heat to the patient's eye for the disclosed embodiment. Six wiresmake up the electronics wiring 126. The six interface wires areconnected to the interface circuitry 98 that is embedded in thedisposable component 74. HEATER+ and HEATER− are connected to theheating element 106 in the lid warmer 90 when the platform 94 isconnected to the controller interface 76. THERM1+ and THERM2+ arecoupled to two thermistors 136A, 136B. The two thermistors 136A, 136Bprovide an indication of temperature at the patient's eyelid as part ofa temperature feedback mechanism to allow the temperature control system132 to monitor the temperature for control. Because in the preferredembodiment, the temperature drop between the heating element 106 and theinside of the patient's eyelid is minimal, regulating temperature issimpler. This is because the thermistors 136A, 136B record temperaturescloser to the actual temperatures at the glands and thus temperatureovershooting is minimized. It is important to attempt to minimizetemperature overshoot so as to not damage the patient's tissue.Temperature thermostats or other more complicated regulation circuitsmay be employed to regulate temperature as well if desired, especiallyif temperature overshooting is an issue. Further, the size of theheating element and power supply could also be selected so that only aknown maximum amount of heat could be generated even if the heatingelement 106 were energized all the time. This would avoid use of aregulation circuit to prevent temperature overshoot.

Two thermistors 136A, 136B are provided for redundancy and errorchecking in the event one fails. Both thermistors 136A, 136B shouldprovide the same signal indicative of temperature. Both thermistors arecoupled to a common RETURN to provide common current return/grounding.Lastly, a FUSE line is provided and linked to a fuse 138, which is alsocoupled to the RETURN line. As will be discussed later in thisapplication, the controller 72 can send a current over the FUSE linesufficient to blow fuse 138. The controller 72 can blow the fuse 138 toprovide an indication that the lid warmer 90 has been previously used.Thus, if the lid warmer 90 is reused, the controller 72 can detect theopen circuit on the FUSE line and know that the fuse 138 has beenpreviously blown.

FIG. 17 illustrates additional components of the pressure control system130 to provide more detail for the disclosed embodiment. The pressurecontrol system 130 contains an electric pump 139 to pump air into thetubing 118. Other types of pumps may be used. A check valve 140 isprovided inline in the tubing 118 between the electric pump 139 and theinflatable bladder 114 to allow the controller 72 to draw in air to thesystem to use to inflate the inflatable bladder 114 without backflowrelease. A relief valve 141 is also provided as a safety measure toensure that line pressure to the eyecup 110 does not exceed maximumpressure settings in the controller 72. As illustrated in FIG. 15 anddiscussed above, the pressure sensor 134 is coupled to the tubing 118 tocommunicate the pressure in the tubing 118 to the pressure controlsystem 130 for various functions.

FIG. 18 illustrates the temperature control system 132 in more detailfor the preferred embodiment. The temperature control system 132includes a power system 142 to provide power to the system components.In the disclosed embodiment, batteries 144 are used as the power supply.Energy from the batteries 144 are provided to a reverse batteryprotection and low battery detection circuit 146. If the batteries 144are low in power, a low battery signal is communicated over a lowbattery signal line 148 to a timer and display controller 150. The timerand display controller 150 is responsible for controlling therapy timersand displaying them on the timer display 88. The timer and displaycontroller 150 is also used to communicate other codes to the userregarding the controller 72, including the low battery signal. Theenergy from the batteries 144 are also routed to various DC-DCconverters 152 to provide various voltage levels needed by thecontroller 72 and its components for operation. Note that the presentinvention is not limited to any particular type of power system orspecific power components.

The temperature control system 132 may also contain a data interface 154to provide pressure and temperature data to a data logger 156. The datalogger 156 may also contain a timer interface 158 to the timer anddisplay controller 150 so that times can be recorded for the data. Thedata logger 156 may be used to record data regarding patient treatmentsfor analysis and/or to provide data for test purposes. The data logger156 may be coupled to a test connector 160 so that logged data regardingthe system may be viewed and/or recorded via an external device (notshown) coupled to the test connector 160.

The remainder of the temperature control system 132 consists of variouscomponents of the controller 72 that provide the overall operation andcontrol of the heat and force application device 70. These componentsare provided in the form of various circuits and control components,including programmable gate arrays (PGA). The components interacttogether to provide a system logic for operation of the system. Thesecomponents will be described in conjunction with FIGS. 21-26 below,which describe the logic control of the system. Note that thesecomponents can be provided by either analog or digital circuitry, andcan be provided using a microprocessor-based architecting, includingsoftware, if desired.

FIGS. 21-26 illustrate the state machine of the controller 72 and thevarious operations performed in the states that provide the operationand logic of the heat and force application device 70. However, beforeturning the state machines and the logic of the various states, a highlevel overall operation of the controller 72 is described with respectto the flowchart of FIG. 19. FIG. 19 will be discussed in conjunctionwith the various states that make up the state machine of the controller72 illustrated in FIG. 19.

FIG. 19 illustrates a flowchart which describes the overall operationand logic of the heat and force application device 70 that is carriedout by the controller 72 and its systems, including the pressure controlsystem 130 and the temperature control system 132, according to anembodiment of the present invention. The process starts by thecontroller 72 resetting in the reset state (step 200 in FIG. 19, resetstate 220 in FIG. 20). The controller 72 always starts in a reset statein the disclosed embodiment. The reset state may occur as a result of apower cycle or if a new disposable component 74 is connected to thecontroller 72. After resetting, the controller 72 performs a series oftests prior to beginning treatment to determine if the controller 72 andits components are operating properly (decision 202 in FIG. 19). If not,an error is noted and the controller 72 stops operation by entering intothe stop state (step 204 in FIG. 19, stop state 224 in FIG. 20). Thestop state disables the heater. If the controller 72 is operatingproperly (decision 202 in FIG. 19), the controller 72 proceeds with theoperations to begin a treatment by entering the run and monitor states(states 226 and 228 in FIG. 20).

As an option, the controller 72 may first blow a fuse on the lid warmer90 to create an open circuit in a fuse blow state (step 205 in FIG. 19,fuse blow state 222 in FIG. 20). This is so a lid warmer 90 cannot bereused for subsequent treatments for safety and contamination reasons.As part of the operation check in decision 202, the controller 72 maydetermine if the fuse on the lid warmer 90 has been blown in the resetstate (220 in FIG. 20). If so, this would be an indication that the lidwarmer 90 has already been used, and the controller 72 would enter thestop state (step 204 in FIG. 19, stop state 224 in FIG. 20). Thecontroller 72 will continue to allow operation with the installed lidwarmer 90 after the fuse is blown until the lid warmer 90 is removed. Insuch case, the controller 72 will enter the reset state (step 200 inFIG. 19, reset state 220 in FIG. 20).

Next, the controller 72 prepares for a therapy. The controller 72 mayfirst initialize therapy timers in the timer and display controller 150.Timers allow the user of the controller 72 to track the amount of timethat therapy has occurred, including heat and force application.Different patients may require different amounts of time for theapplication of heat and force during treatments. For example, atreatment cycle may include the application of heat for three minutes,but force may need to be applied, disengaged, and reapplied severaltimes during the three minute therapy time period.

Subsequently, the controller 72 enables the temperature control system132 and the pressure control system 130 to apply heat and force to thepatient's eyelid as part of a run state (step 208 in FIG. 19, run state226 in FIG. 20). In the disclosed embodiment of the lid warmer 90 andeyecup 110, heat is applied to the inside of the patient's eyelid, andforce is applied to the outside of the patient's eyelid, as previouslydiscussed. However, note that the controller 72 could also be used toapply heat and/or force to any part of the patient's eye or supportingstructure, including but not limited to both to the outside of thepatient's eyelid, and heat to the outside and force to the inside of thepatient's eyelid. The controller 72 then monitors the temperature andforce applied to the patient's eyelid as part of the heat and pressureregulation in a monitor state (step 210 in FIG. 19, monitor state 228 inFIG. 20). The run and monitor states 226, 228 operate simultaneously inthe preferred embodiment so that heat and force are constantly beingapplied and temperature and pressure monitored during therapy. If duringthe run or monitor 226, 228, an error is detected (decision 212 in FIG.19), the controller 72 enters the stop state to discontinue therapy(step 216 in FIG. 19, stop state 224 in FIG. 20). If an error is notdetected, the run and monitor states 226, 228 continue until either anerror is detected (decision 212 in FIG. 19) or the therapy is completed(decision 214 in FIG. 19).

FIGS. 21-26 illustrate flowcharts that detail the operation of thevarious states executed by the controller 72 to control temperature andpressure to provide MGD treatment, according to the disclosedembodiment. Each of these states were described generally above withrespect to the flowchart in FIG. 19 and the state diagram in FIG. 20.Now, each state and their specific operations and functionalities as itcontributes towards the operation of the heat and force applicationdevice 70 and its controller 72 will be described in more detail. Sincesome operations require information from various components in thepressure and temperature control systems 130, 132, references to thesevarious components will be made as the operations of the states aredescribed. This includes reference to components previously and notpreviously introduced in the temperature control system 132 in FIG. 18.

FIG. 21 illustrates a flowchart of the reset state 220 (step 230). Thecontroller 72 enters the reset state 220 when either a power cycleoccurs or a new disposable lid warmer 90 (with an intact fuse 138 as anoptional feature) is installed (step 232). Thereafter, the controller 72checks to determine if the power supply voltage is above a set minimumvoltage level (decision 234). In the disclosed embodiment, the batteries144 must provide at least 2.4 Volts. If they do not, an battery error(e.g. “bAt”) is displayed on the timer display 88 (step 236). Referringto FIG. 19, the low battery error is displayed by timer and displaycontroller 150 on the timer display 88 in response to the low batterysignal sent from the low battery detection circuit 146 over the lowbattery signal line 148.

If the batteries 144 are producing a sufficient voltage, the controller72 continues with the reset state 220 by next determining if thedisposable component 74 is installed (decision 238). If not, thecontroller 72 is not ready for operation. However, before going to thestop state 224 (step 246), the controller 72 takes the opportunity toperform a pressure diagnostic test. Referring to FIG. 18, the pressuresensor 134 signal indicative of measured pressure in the tubing 118 iscommunicated to a pressure level comparator 162, which communicates thepressure level to the pressure display 84 and to an error checkingcontrol system 164. Ideally, the pressure in the tubing 118 should notbe greater than ambient pressure. If the pressure sensor 134 does notprovide a signal indicative of ambient pressure (decision 240), this isan indication that the pressure sensor 134 may not be operatingproperly. Thus, a pressure sensor 134 error message (e.g. “E_(—)4”) maybe displayed on the timer display 88 (step 244), via the ERRORS signalline 171 (see FIG. 18), before the controller enters the stop state 224(step 246). If the pressure sensor 134 is properly measuring pressure,the timer display 88 remains in the reset display state (e.g.“_(— — —)”) (step 244) and the controller 72 waits until a disposablecomponent 74 is installed (decision 238). Note that because ambientpressure may not be 0 mm Hg depending on where the heat and forceapplication device 70 is located, a threshold pressure level is used. Inthe disclosed embodiment, the threshold pressure level is 1 psi.

Once the disposable component 74 is installed, the controller 72 cannext optionally determine if the fuse 138 on the lid warmer 90 is blown(decision 248). This check is only performed if the lid warmer 90 isequipped with a fuse 138 that can be blown by the controller 72 toindicate when the disposable component 74 has been previously used for atreatment. In this instance and referring to FIG. 18, a fuse detect andblow circuit 168 communicates a fuse detect signal over the FUSE DETECTline 173 from the interface circuitry 98 on the disposable component 74to the error check controls system 164. This is so the controller 72 candetermine if the disposable component 74 has been previously used. Ifthe fuse 138 is blown, the controller 72 will not allow therapy to beprovided using the currently installed disposable component 74 forsafety and sterility reasons until the disposable component 74 isreplaced with a previously unused disposable one (which will have anintact fuse 138 on the interface circuitry 98). The controller 72 willdisplay an error message (e.g. “E_(—)1”) on the timer display 88, viathe FUSE signal line 170 to indicate to the user that the disposablecomponent 74 must be replaced (step 250) before going to the stop state224 (step 252).

If the fuse 138 is not blown on the disposable component 74 (decision248) or if the fuse check feature is not included in the controller 72,the controller 72 next determines if the heating element 106 isconnected (decision 253). If not, the controller displays a connectmessage (e.g. “Con”) on the timer display 88 to indicate to the userthat the heating element 106 (i.e. the lid warmer 90) is not connectedto the controller 72 and thus therapy cannot begin (step 255). Once theheating element 106 is connected to the controller 72, the controller 72next determines if the temperature level at the lid warmer 90 is lowerthan room or ambient temperature (decision 254). If so, this is anindication that the disposable component 74 may not be installed on apatient's eyelid such that the user is ready for the controller 72 tobegin therapy. Referring to FIG. 18, thermistor conditioning circuits172A, 172B communicate signals from each of the thermistors 136A, 136Bat the disposable component 74 to the error checking control system 164.In response, the connect message (e.g. “Con”) may again be displayed onthe timer display 88 (step 255). The controller 72 will continue tocheck the heating element 106 connection and the temperature at the lidwarmer 90 until the thermistors 136A, 136B read a temperature of roomtemperature or greater (decision 254). This provides some assurance thatthe disposable component 74 is installed on the patient.

Next, the controller 72 will check to determine if the temperature levelat the lid warmer 90 is lower than body temperature (e.g. 30 degreesCelsius) (decision 254). This enables the controller 72 to determine ifthe disposable component 74 is installed on the patient's eye, becauseif so installed, the temperature at the lid warmer 90 should be at leastbody temperature. If the temperature at the lid warmer 90 is not atleast body temperature, an error message (e.g. “LO”) may be displayed onthe timer display 88 in response to indicate to the user that thetemperature at the lid warmer 90 is abnormally low (step 256). Thecontroller 72 will thereafter cycle back through the series of checks toensure that the lid warmer 90 is properly installed and ready for use intherapy (decisions 253, 257, 254, 258).

Once the temperature of the lid warmer 90 is at or above roomtemperature (decision 254), the controller 72 then determines if thetemperature at the lid warmer 90 is at a temperature level that ishigher than would be expected before therapy has begun (i.e. an overtemperature level, e.g. 30 degrees Celsius) (decision 258). This may beindicative of an ambient temperature that is deemed to high to begintherapy. If so, an error message (e.g. “E_(—)6”) may be displayed on thetimer display 88 by the error check control system 164 (step 260) beforethe controller 72 enters the stop state 224 (step 262). If not, thecontroller will check the pressure level in the tubing 118, via thepressure sensor 134, to ensure pressure level is at ambient pressuresince the controller 72 has not inflated the bladder 114 to generate apressure to the patient's eyelid (decision 264). If the pressure levelis lower than ambient pressure, this may be an indication of an error,such as an error with the pressure sensor 134 or the power source. Ifthe pressure level is lower than ambient pressure, the controller 72will check to determine if the battery voltage is sufficient (decision261) and repeat through the series of checks (decisions 253, 257, 254,258, 264) before allowing therapy to start. Once these series of checkshave been satisfied, therapy can begin. In response, the controller 72will cause the timer display 88 to be reset to indicate the beginning ofa therapy session (e.g. a 180 second countdown)(step 265). Thecontroller 72 will then check to ensure that the pressure level in thetubing 118 is not higher than ambient pressure or a desired pressurelevel that would be indicative of a pressure sensor 134 or other problem(decisions 267, steps 269, 271) before proceeding to the run state 226,or the fuse blow state 222 if provided (step 268).

After leaving the reset state 220, the controller 72 may go into thefuse blow state 222 (step 272), which is illustrated in FIG. 22. Ifprovided, the controller 72 blows the fuse 138 on the lid warmer 90 sothat it cannot be reused after the controller 72 is reset (step 273).Referring to FIG. 18, the error checking control system 164 causes asufficient current to be sent over the FUSE BLOW line 174 and to thefuse detect and blow circuitry 168 to blow the fuse 138 at thedisposable component 74. The controller 72, via the error check controlsystem 164, then checks to see if the fuse 138 was successfully blownvia the FUSE DETECT line 173 (decision 274). If not, and after sevenunsuccessful attempts to do so (decision 276), an error message (e.g.“E_(—)7”) may be generated on the timer display 88 (step 278) beforegoing to the stop state 224 (step 280). It the fuse 138 is successfullyblown, the controller 72 is ready to provide therapy. The controller 72enters the run and monitor states 226, 228 (step 282) to be executedsimultaneously to apply heat and force to the patient's eyelid as wellas monitor the temperature and pressure applied for control purposes.

FIG. 23 illustrates the run state 226 (step 300). The controller 72enters the run state 226 to begin therapy either from the reset state220 (step 268 in FIG. 21) or optionally from the fuse blow state 222(step 282 in FIG. 22). The run state 226 will be discussed before themonitor state 228, which is illustrated in FIGS. 25A and 25B. Turning toFIG. 23, the run state 226 begins by the controller 72 initializing acycle timer and beginning a count down timer at the count down timevalue programmed into the system (step 302). Turning to FIG. 18, thetimer and display controller 150 resets the timers. The count down timeris displayed on the timer display 88. The cycle timer will cause thetimer display 88 to blink at the end of a cycle such that the timerdisplay 88 is used to provide the cycle timer and countdown timerinformation to a user.

In the disclosed embodiment, the cycle timer is the amount of time thatforce should be applied continuously to the patient's eyelid beforebeing released. In the disclosed embodiment, this is set at one minute.The count down timer is the total therapy time for heat to be applied tothe patient's eyelid. In the disclosed embodiment, the count down timeris set at three minutes. Thus, there will be three cycles during thetherapy. The timers are not only used to provide a visual timingindicator to the user, but are also used to control heat and forceapplication to the patient's eyelid as will be further discussed. Thesetimer values could also be based on programming instructions provided bythe user to the controller 72.

Thereafter, the temperature control system 132 enables heat to beapplied to the patient's eyelid via the lid warmer 90 and its lens (step304). The beginning of heat therapy is signaled to the user by flashingthe decimal point on the timer display 88 in the disclosed embodiment(step 304). Referring to FIG. 18, the therapy timer controller 150causes an enable signal to be generated over an ENABLE line 176 toactivate a lid warmer controller 178 to apply an electrical signal tothe HEATER+ and HEATER− lines in the electronics wiring 126 (see FIG.16). This causes the heating element 106 in the lid warmer 90 toenergize and generate heat to the patient's eyelid. The lid warmercontroller 178 controls the heating element by turning on and off theelectrical signal to the heating element 106. However, any type ofheating control can be employed, including but not limited to PWMtechniques. Thereafter, the timer and display controller 150 determinesif the cycle timer has not expired (decision 306). If it has expired,the therapy timer is paused (step 308) and the pause state 229 isentered (step 310). This is because the force must be released beforetherapy can continue. The pause state 229 is illustrated in FIG. 24 andwill be discussed later below.

If the cycle timer has not expired (decision 306), a start, alert,therapeutic temperature, and therapeutic pressure flags are checked(decisions 312, 314, 316, 318). These flags are set by the monitor state228 as part of error checking, which is illustrated in FIGS. 25A and 25Band will be discussed later below. At this point, all that is requiredto understand is that these flags being set means that heat therapy cancontinue. If not, either the stop state 224 (step 317) or the pausetherapy timer state 229 (step 308, 317) will be entered before returningback to the run state 226. If the flags are properly set, the therapytimer will be decremented with the elapsed time as each second elapses(steps 319, 320) with heating element 106 continuing to be energized toproduce heat at the lid warmer 90 until the therapy time is complete(decision 322). When the therapy time has completed, meaning that thetherapy timer time has counted down to zero time in the disclosedembodiment, the therapy timer is stopped (step 324) and the stop state224 is entered to discontinue heating the patient's eyelid (step 326).

Before describing the monitor state 228, which is illustrated in FIGS.25A and 25B, the pause state 229 will next be described. The pause state229 is illustrated in FIG. 24. The pause state 229 is entered to disableenergizing the heating element 106 and wait for the user to release theforce lever 86 (or other pressure control mechanism) before re-enteringthe run state 226. This ensures that force is not continuously appliedto the patient's eyelid during the entire therapy session without somerelief to allow blood flow in the eyelids for safety precaution reasons.The timer and display controller 150 first disables the heating element106 by removing the enable signal from the ENABLE line 176 to the lidwarmer controller 178 (step 332). The timer display 88 is paused fromchanging, and the cycle time is flashed indicating that the end of thecycle has occurred (steps 334, 338). The start flag is checked(decisions 336, 340) to ensure that the user has released force so thattherapy can be restarted, in which case the system returns back to therun state 226 (step 342). The start flag is set and reset in the monitorstate 228.

If the start flag is set (decision 336, 340), the controller 72 may alsocheck to determine if the temperature at the lid warmer 90 is above adefined threshold temperature level. If so, this may be indicative ofthe heating element 106 producing a heat exceeding an upper temperaturelevel of heat to be applied to the patient (decisions 337, 343). In thedisclosed embodiment, this upper temperature threshold level is 43degrees Celsius. However, this threshold temperature level can be set tobe any temperature level threshold desired. If the threshold temperaturelevel is exceeded, the temperature display 82 may be flashed to indicatethis condition to the user as well as an error (e.g. “E_(—)3”) beingdisplayed on the timer display 88 (step 341, 343) before the controller72 enters the stop state 224 (steps 343, 349).

The monitor state 228 is illustrated by the flowchart of FIGS. 25A and25B. The monitor state 228 will continuously check the temperature andpressure applied to the patient's eyelid. Temperature is checked usingthermistors 136A, 136B, and pressure is checked using pressure sensor134 coupled to the tubing 118. The results of the measured temperatureand pressure are displayed on the controller 72, via the temperature andpressure displays 82, 84. The temperature and pressure measurements areanalyzed to ensure that no error conditions have occurred. In addition,the monitor state 228 will signal to the run state 226, which isexecuting simultaneously with the monitor state 228, when therapeutictemperatures and pressures have been reached.

Turning to FIG. 25A, the temperature control system 132 determines ifthe temperature is above a threshold maximum temperature level failsafefor safety reasons (decision 352). This threshold maximum temperaturelevel may be set to 45 degrees Celsius. If so, the over temperaturecondition is flashed on the temperature display 82 to indicate to theuser that the temperature is over the allowed temperature setting (step354). Further, an error message (e.g. “E_(—)3”) may be displayed on thetimer display 88 in the same regard (step 356). The controller 72 willenter the stop state 224 (step 358) to halt therapy. If the temperatureat the lid warmer 90 is not above the set safe temperature threshold,the error checking controller checks to see if the two temperaturethermistors 136A, 136B are different in value (decision 360). Thethermistor 136A, 136B providing the higher reading is used fortemperature monitoring as an additional precaution to prevent an unsafetemperature from being applied to the patient's eyelid (steps 362, 364).The measured temperature is then displayed on the temperature display 82(step 366).

The temperature at the thermistor 136A, 136B used to measure thetemperature is checked again to ensure that the temperature at the lidwarmer 90 has not exceeded the maximum allowable temperature again as asafety precaution (decision 368). If the temperature has exceeded themaximum allowable temperature, the same steps previously performedearlier for this check are performed (steps 354, 356, 358). If not, theheater switch driver in the lid warmer controller 178 may be optionallychecked to ensure that it is working correctly to ensure that heat willnot be applied to the patient's eyelid when the switch is turned off viathe ON/OFF signal line 180 in FIG. 18 (decision 370). If the heaterswitch driver has a malfunction, and error message (e.g. “E_(—)7”) maybe generated on the timer display 88 to indicate the hardware failure tothe user (step 372). The system then enters the stop state (224) todisable the application of heat (step 374).

If the heater switch driver is operating properly (decision 370), thesystem determines if the pressure level in the tubing 118 is above themaximum allowable pressure as a safety precaution to prevent too muchpressure from being applied to the patient's eyelid (decision 376). Ifso, the over pressure condition is displayed on the pressure display 84and the timer display (e.g. “E_(—)5”) to indicate the over pressurecondition to the user (step 378, 380) before entering the stop state 224(step 382). If no over pressure condition exists, the measured pressureis displayed on the pressure display 84 (step 384).

Next, as illustrated in FIG. 25B, the system determines if thetemperature at the lid warmer 90 is above the therapeutic temperaturesetting (decision 386). This is an indication that the temperature hasrisen at the lid warmer 90 necessary to provide therapy and so that thetherapy timer will accumulate in the run state 226. The therapeutictemperature setting is set by the system. Alternatively, it may beprogrammed by the user into the controller 72. If the temperature isabove the therapeutic temperature setting (decision 386), thetherapeutic temperature flag is set (step 388). If not, the therapeutictemperature flag is cleared (step 390).

In a similar manner to temperature, the system also determines if thepressure in the tubing 118 indicative of the pressure applied to thepatient's eyelid is above the therapeutic pressure setting (decision392). This is an indication that the pressure has risen to a levelnecessary to provide therapy and so that the therapy timer willaccumulate in the run state 226. The therapeutic pressure setting is setby the system. Alternatively, it may be programmed by the user into thecontroller 72. If the pressure level is above the therapeutic pressuresetting (decision 392), the therapeutic pressure flag is set (step 394).If not, the therapeutic pressure flag is cleared (step 396). The systemalso checks to determine if the pressure level has increased to aminimum threshold level indicative of the force lever 86 being engagedby the user to allow therapy to start (decision 398). If so, the startflag is set (step 400). If not, the start flag is cleared (step 402).

The system also monitors the temperature thermistors 136A, 136B todetermine if their measured signals track each other as an indication ofwhether the thermistors 136A, 136B may have malfunctioned (decision404). Two thermistors are unlikely to produce the same output for agiven temperature, but they change in like kind in response to the sameconditions. If they are properly tracking each other, the alert flag iscleared indicating that no error condition exists for the thermistors(step 406). If not, an error message (e.g. “E_(—)2”) may be displayed onthe timer display 88 (step 408) before the alert flag is set (step 410).As previously discussed, the run state 226 checks the alert flag as acondition of allowing therapy to continue. The monitor state 228continues to execute in a looping fashion until a condition occurs toplace the controller 72 in the stop state 224.

FIG. 26 illustrates the last state of the controller state machine, thestop state 224. The stop state 224 is entered when the total therapytime has reached its preset maximum time or any error condition occurs(step 420). Once in the stop state 224, the controller 72 cannot berestarted with the same disposable component 74 for safety reasons. Theheating signal to the heating element 106 is disengaged to stop heatfrom being applied to the patient's eyelid (step 422). Further, thepower supply to the heating element 106 can also be disabled as afurther measure to ensure that heat will no longer be applied to thepatient's eyelid (step 423). An optional test connector may be installedto download sensor or other operational data to memory for data loggingor for testing. If installed (decision 424), the data may be downloadedto memory (step 426). Once the treatment data is downloaded, thecontroller 72 can check the status of the battery until the controller72 is reset to enter the reset state 230 (see. FIG. 21), since thecontroller 72 is not performing therapy and is otherwise dormant(decision 428, step 430). If the test connector is not installed, thecontroller 72 continues to check for installation of the optional testconnector as well as performing a battery level check (decision 425,step 427) until either installed or the controller 72 is reset to enterthe reset state 220 (see FIG. 21). Thereafter, the system enters the runstate 226, in which case, therapy can begin again once the errorconditions are eliminated and a new disposable component 74 isinstalled.

FIGS. 27-30 illustrate an alternative embodiment of the disposablecomponent 74B that may be employed by the present invention to applyheat and/or force to the patient's eyelid as part of treating MGD. Asillustrated in FIGS. 27 and 28, the apparatus comprises an insulator 440and a means for applying force to the eyelid 91A, 91B, or lens 440 Inthe most basic form, the insulator 440 is concave in shape and mirrorsthe curvature of the eyeball 442, substantially similar to a contactlens. As employed herein, the term “insulator” is intended to includeany component or material wherein there is greater resistance to thermalconduction or radiation towards the surface of the eye than towards theeyelid. Stated alternatively, in the insulator thermal energy radiatesmore easily towards the eyelid than towards the eyeball surface in orderto minimize the possibility of causing injury to the eyeball 442. In themodel that was constructed, the diameter was sufficient to more thancover the cornea or in the approximate range of 15 mm to 25 mm would besufficient for most eyes assuming a corneal relief zone of approximately16 mm. It will be noted however, that the diameter of the insulator 440can vary beyond the ranges stated above.

Further, the insulator 440 is constructed from a biocompatible materialsuch as polymethylmethacrylate (PMMA), or in the case of the prototypethat was constructed, epoxy or other materials well known to thoseskilled in the art. The insulator 440 may be flexible, but ideallyshould be only minimally compressible, as will become clear from thediscussion that follows. According to the invention, the insulator 440is inserted on the surface of the eye 442, behind the rear surface ofthe eyelid and should include smooth edges so as not to scratch or cuteither the eyelid or the eye. As used herein the term “eyelid” or“eyelids” is intended to include the upper lid and the lower lid, eitherin singly or in combination. The insulator 440 provides a back plateagainst which force may be applied. In limited circumstances when theobstruction in the meibomian gland channel is minimal, the meibomiangland may be cleared merely through the application of force externallyapplied to the eyelid, such as gentle finger press. More specifically,with the insulator 440 in place behind the eyelid, finger pressure isapplied to the external surface of the eyelid, the eyelid being“sandwiched” between the finger and the insulator 440.

In other instances, the meibomian gland obstruction may be blocked to adegree greater than can be treated with simple pressure alone. In suchcases it is necessary to apply thermal energy to the eyelid in order toloosen, break up, fracture, soften or liquefy at least a portion of theocclusion. Thermal energy may be applied by any one of the well knownmeans for applying thermal energy such as modalities such as resistive,IR (infrared), ultrasonic heating, microwave, any one of the numerous“hot pads” that chemically produce an exothermic reaction or in thesimplest form a hot compress. Experimentation has revealed that in orderto be clinically effective the eyelid should be heated to a temperatureof between about 35 degrees Celsius and 47 degrees Celsius. The lengthof time for which thermal energy (i.e. heat) is applied to the eyeliddepends upon the extent that the obstruction blocks the meibomian glandchannel as well as the composition of the obstruction. In very minorcases, heat may be applied to the eyelid for less than three minutes oreven as little as five to fifteen seconds. On the other hand, extremeblockage may require as much as thirty minutes of heating to melt,loosen, or soften the obstruction prior to the application of force tothe eyelid to express the softened obstruction. Experimentation hasfurther revealed that the eyelids are efficient heat exchangers withcirculating blood acting as the cooling mechanism and that the eyelidtemperature returns to normal in less than two minutes at which time theobstruction re-hardens making extraction difficult. It is thereforenecessary to apply the aforesaid expressive force to the eyelid withinthat time frame in order for the treatment to be successful. Thus,gentle finger pressure, preferably in a milking type action, to urge theobstruction upward and out of the meibomian gland orifice should beemployed. Again, depending on the nature and location of theobstruction, mere compressive force may be effective in some instances.

The insulator 440 is inserted between the rear of the eyelid on thesurface of the eyeball 442, as previously described. An eyecup 447 isemployed to provide force and thus pressure to the eyelid. In oneembodiment of the invention, thermal energy is applied as describedabove such as with a hot compress, and thereafter, within the one to twominute time frame, an eyecup (which may be unheated) is placed on theouter surfaces of the eyelid and force is applied thereto to express thesoftened obstruction. As illustrated, the eyecup mirrors the size andshape of the eyelids when closed.

In FIGS. 29 and 30, the insulator 440 is provided with a heater means orheater 448. In this embodiment, the insulator 440 (e.g. lens) is concavein shape; however, the curvature is greater than that of the eyeball 442so that an air pocket is formed between the insulator 440 and theeyeball 442. The air pocket provides additional insulation to preventthe heat applied from being conducted to the eyeball 442 surface duringthe treatment time. Further, ends 450 of the insulator 440 will be theonly portion that actually physically contacts the eyeball 442. Thissection of the insulator 440 may be constructed of a biocompatiblematerial that will not scrape or abrade the eyeball surface such as asoft rubber, plastic, or possibly even a soft metal. It will be notedthat the lower surface 452 (i.e., that portion beneath the heater 448)and the upper surface 454 (i.e., that portion above heater 448) may befabricated from different materials in order to minimize thermalconduction towards the eyeball and to facilitate thermal conductiontowards the eyelid. One method of accomplishing the foregoing is toprovide small air pockets in the lower surface 452 which would addadditional insulation to that layer.

Heater 448 may be a resistive type heater, a thick film heater, or anyone of a number of other types, such as a “flex circuit” (etched metalon flexible substrate) well known to those skilled in the art. As shownin FIG. 30, the insulator 440 is provided with a gripping means, handle,or platform 456 in which heater terminals 458 connect to the heater 448,battery 460, a thermal controller unit 462 (i.e. temperature regulator),and on/off switch 464 are located. The circuit comprising the heater448, a power source such as battery 460, thermal controller unit 462,and on/off switch 464 are connected in series. The thermal controllerunit/thermal regulator 462 is selected so that the temperature may becapped at an upper temperature threshold, such as at 47 degrees Celsiusfor example. The thermal controller unit 462 may also be designed to andturn off the circuit when that temperature is exceeded in order toprevent damage to the eye and surrounding tissue. In an alternateembodiment, the heater 448 may be connected to an “off device” powersource through the use of appropriately placed contacts 466 and 468 (seeFIG. 29).

Referring now back to the disposable component 74B of FIGS. 26-29, apair of opposing spaced apart cantilevered arms 470 extendperpendicularly outward from the outer surface of the insulator 440 andtogether with handle 456 define means for coupling the eyecup 447 to theinsulator 440. The respective arms 470 are tapered towards each otherand each includes a notch 472 the purpose of which will become evidentas the description proceeds. As best illustrated in FIG. 6, the heater448 fits into a corresponding depression in the insulator 440 such thatthe two surfaces are flush in order to provide a smooth even surface forthe inner eyelid to prevent rubbing and chaffing which upon blinking.Alternatively, the heater 448 could be embedded within insulator 440 orapplied or connected to the surface thereof and with a smoothing coatingoverlay being added.

The eyecup 447 is adapted to overlie the outer surface of the eyelid,substantially conforms to the surface shape thereof and is adapted tocooperate with the insulator 440. The eyecup 447 includes a centrallylocated longitudinal slot 474. Positioned on above and below slot 474and extending perpendicularly outward from the body of eyecup 447 is apair of flexible spaced apart opposing cantilevered engagement arms 476which include integrally molded finger grips or handles 478 andextensions 468. Positioned on the underside of eyecup 447 is a pair ofdiaphragms 480, which are in fluid communication with each other andwhich includes an inlet means or inlet 482. The diaphragms 480 areattached to the eyecup 447 via conventional means, such as glue forexample (not shown). Further, it will be noted from the drawings thatthere is sufficient space provided between the diaphragms 480 to permitthe arms 470 to pass therethrough.

While not illustrated, it will be noted that the eyecup 447 could beprovided with a single diaphragm 480 with a hole defining an openingthrough which the arms 470 may pass. The diaphragms 480 may befabricated from a biocompatible material such as polyurethane foam (openor closed cell), a sealed air balloon, or a gell-filled bladder. Again,depending upon the type and degree of obstruction, the diaphragms willvary in thickness and/or durometer. In an alternate embodiment, thediaphragms 480 may comprise bladders which may be fabricated from anyflexible, expandable material such as rubber or plastic. However, it ispreferred that the coefficient of expansion be linear with respect tothe amount of fluid added. The bladders 480 may be partially filled orinflated with a constant amount of fluid or they may be provided with arudimentary pump connected to inlet 482 such as is used with a perfumeaerosolizer. The fluid is preferably air, but may also be a liquid suchas water, saline, etc. Further, while not shown, the fluid may also beheated in order to assist in the softening of any meibomian glandobstructions which may be present. It will be noted that for any givenpatient, either or both of the insulator and fluid may be heated asrequired in order to soften any given obstructed meibomian glands.

While not illustrated, the bladders 480 could be fabricated in such amanner that as they inflate, pressure is applied which urges thesoftened gland obstructive material up the gland channel and out of thegland orifice to clear the gland. One method would be to increase thethickness of the bladders 480 such that there is less resistance (lessthickness) to inflation near the bottom of the gland and the resistanceincreases (greater thickness) as one reaches the gland orifice.

In operation, the insulator 440 is placed on the sclera of the eye 442in much the same manner as a contact lens is inserted. When properlypositioned, arms 470 will extend outward between the eyelids 91A, 91B.The eyecup 447 is then positioned with the concavity facing the eyelid91A, 91B such that the notch ends of arms 470 are inserted into slot474. The eyecup 447 is directed along the arms 470 until notches 472engage arm extensions 468 thus coupling the eyecup 447 to the insulator440 and connecting contacts 466, 468. The heater 448 is then activatedby switch 446 or other means to which the heated fluid in bladders 480may be added simultaneously or serially for the preselected period oftime, for example, two minutes. Thereafter, or simultaneously with theapplication of heat, the bladders 480 may be expanded which will urgethe softened meibomian gland sebum up and out of the gland channeltowards the gland orifice, thus, unblocking the gland. When treatment iscomplete, finger grips 478A, 478B are then pressed towards each other sothat the eyecup 447 is free to slide off of and be removed from the arms470. Thereafter, the insulator 440 is removed from the eyeball 442 andtreatment is complete.

It will be noted that various mechanisms to lock the insulator to theeyecup could be employed, such as a ratchet type mechanism on arms 470which is released upon compression of finger grips 478A, 478B, a pressfit of the arms 470 into slot 474 as well as other mechanisms well knownto those skilled in the art, not discussed herein. Manual control andrelease and force as well as manual adjustment of the eyecup may beemployed during treatment and/or until expression of the obstruction orocclusion in the meibomian glands is achieved. While not specificallyrequired, it is preferable that the locking mechanisms be near “zeroinsertion” force in order to minimize the potential for eye injury.Further, different eyecups with different shapes and differentrigidities may be employed. Some of these alternate disposablecomponents 74 are disclosed in FIGS. 31-40 of the present applicationand will be discussed below.

FIGS. 31A and 31B illustrate another alternative embodiment of thedisposable component 74C that may be employed by the present inventionto apply heat and/or force to the patient's eyelid as part of treatingMGD. In this embodiment, the lid warmer 90C is firmly affixed to theeyecup 110C without the ability to separate the two or make adjustmentsto change the distance between the lens 90C and the eyecup 110C. Theonly moveable component is an inflatable bladder 114C that is controlledto apply a force to the outside of the patient's eyelid. Such adisposable component 74C may be employed as simpler to install and useby technicians during therapy since no adjustments to the position ofthe eyecup 110C with respect to the lid warmer 90C are necessary.

The disposable component 74C comprises a lid warmer 90C in the form of alens similar to previously discussed lid warmer 90A, 90B. The lid warmer90C contains a heating element (not shown) to apply heat to the insideof the patient's eyelid when the inside surface of the lens 93C isplaced on top of the patient's eye. The lid warmer 90C also contains alid warmer platform 94C to allow a technician or doctor to grasp the lidwarmer 90C and install it over top of the patient's eye. An eyecup 110Cis also provided to apply force to the outside of the patient's eyelid.The eyecup 110C is formed by an upper and lower concave cups 471A, 471B.An opening 473 is provided between the two cups 471A, 471B about ahorizontal center line of the lens 90C for ease in making adjustmentsand because the meibomian glands are located above and below the centerof the lens. Thus, it may not be necessary to apply force in the centerof the eyecup 110C where the upper and lower eyelids of the patient meettogether when the disposable component 74C is installed. The lid warmerplatform 94 is securely fixed to the eyecup 110C at an interface section475 to provide a fixed distance between the inside of the eyecup 110Cand the outside surface of the lens 92C

FIG. 32 illustrates another alternative embodiment of the disposablecomponent 74D that may be employed by the present invention to applyheat and/or force to the patient's eyelid as part of treating MGD. Inthis embodiment, the eyecup 110D contains a latching mechanism 116D thatallows the eyecup 110D to be affixed to the lid warmer platform 94D andthe distance between an inflatable bladder 479A, 479B and the outsidesurface of the lens 92D to be adjusted.

In this embodiment, the eyecup 110D design contains split upper andlower eyecups 481A, 481B similar to the eyecup 110C design illustratedin FIG. 31, except that the eyecups 481A, 481B that support membranes orbladders 479A, 479B to apply force to the patient's eyelid arecompletely separated from each other. The split eyecups 481A, 481B allowthe upper eyecup 481A to be lifted independent of the lower eyecup 481Bto be able to release the eyecup 110D from the lid warmer 94D. In thisregard, the lid warmer platform 94D contains holders 483 that areadapted to secure an eyecup platform 485 attached to the eyecup 110D tosecure the eyecup 110D to the lid warmer 94D. The eyecup platform 485contains a clamp 484A hingedly attached to the lid warmer platform 94Dvia hinge 487. The lid warmer platform 94D contains an opposing clamp484B, such that when the clamps 484A and 484B are squeezed together, theeyecup platform 485 is released from the holders 483 to release theeyecup 110D from the lid warmer 94D. The lid warmer platform 94D alsocontains a grip handle 493 that can be held while the clamps 484A, 484Bare squeezed to hold the lid warmer 94D when the eyecup 110D isreleased.

FIG. 33 illustrates another alternative embodiment of the disposablecomponent 74E that may be employed by the present invention to applyheat and/or force to the patient's eyelid as part of treating MGD. Thisembodiment is similar to the disposable component 74E of FIG. 32, exceptthat the latching mechanism 116E to attach and release the eyecup 110Efrom the lid warmer 90E is provided completely as part of the eyecup110E. The latching mechanism 116E allows the eyecup 110F to be affixedto the lid warmer platform 94E and the distance between an inflatablebladder 490A, 490B and the outside surface of the lens 92E to beadjusted.

In this embodiment, the eyecup 110E design contains a split upper andlower eyecups 491A, 491B similar to the eyecup 110E design illustratedin FIG. 32. The upper and lower eyecups 491A, 491B support membranes490A, 490B that apply force to the patient's eyelid. Eyecup platforms492, 496 extend from the eyecup 110E and contain clamps 494A, 494Bhingedly attached to each other via hinge 493. When the clamps 494A and494B are squeezed together, the eyecup platforms 492, 496 move away fromeach other to release the lid warmer platform 94E. The lid warmerplatform 94E was compressed between the eyecup platforms 492, 496 whenthe clamps 494A, 494B were not being squeezed to secure the lid warmer90E to the eyecup 110E. The eyecup 110E can be adjusted with respect tothe lid warmer 90E by compressing the clamps 494A and 494B and movingthe eyecup platforms 492, 496 to the desired location on the lid warmerplatform 94E. The lid warmer platform 94E may also contain a grip 489 atits end to provide better gripping of the lid warmer platform 94E whenthe eyecup 110E is adjustably placed at the desired location along thelid warmer platform 94E.

FIG. 34 illustrates another alternative embodiment of the disposablecomponent 74F that may be employed by the present invention to applyheat and/or force to the patient's eyelid as part of treating MGD. Thisembodiment has a latching mechanism 116F similar to the disposablecomponent 74E of FIG. 33, except that the eyecup 110F is one piecehaving an eyecup 504 that does not contain separable components. Thelatching mechanism 116F allows the eyecup 110F to be affixed to the lidwarmer platform 94F and the distance between an inflatable bladder 502,490B and the outside surface of the lens 92F to be adjusted. The eyecup110F contains a pneumatic interface 508 to allow the controller 72 toinflate the bladder 502.

The eyecup 110F also contains an eyecup platform 510 that supports thelatching mechanism 116F. The eyecup platform 510 supports eyecups 504A,504B that support a membrane or bladder 502 to apply force to thepatient's eyelid. The latching mechanism 116F is comprised of eyecupclamps 512A, 512B that are hingedly attached to each other via hinge513. When the clamps 512A and 512B are squeezed together, an orifice 514in the eyecup platform 5101 is unlocked to allow the lid warmer platform94F to be moved transversely along the eyecup platform 510F. In thismanner, the lid warmer 94F can be affixed to the eyecup 110F and movedto the desired distance from the eyecup 110F. If the lid warmer 90F andits platform 94F are pulled away from the eyecup 110F, the lid warmer90F can be released from the eyecup 110F when platform 94F is pulledthrough the orifice 514. Just as the platform 94F in FIG. 33, the lidwarmer platform 94E may also contain a grip 500 at its end to providebetter gripping of the lid warmer platform 94F when the eyecup 110F isadjustably placed at the desired location along the lid warmer platform94F.

FIG. 35 illustrates another alternative embodiment of the disposablecomponent 74G that may be employed by the present invention to applyheat and/or force to the patient's eyelid as part of treating MGD. Thisembodiment has a latching mechanism 116G that operates similar to themanner in which a syringe works. The eyecup 110G is formed from onepiece. An outer surface of the eyecup 522 is attached to acylindrically-shaped tube 524 having a platform 526 on its end. The lidwarmer platform 94G extends through the tube 524 and an orifice 528through the platform 526 and contains a lid warmer platform 94G in theform of a plunger 520 on its end that rests against the platform 524when fully pushed down or engaged. To move the eyecup 90G farthest fromthe lid warmer 90G, the plunger 520 is fully engaged forward ordownward. To move the lid warmer 90G closer to the eyecup 110G, theplunger 520 is pulled upward or backwards. The plunger 520 controls themovement of the lid warmer 90G and thus the distance between the lidwarmer 90G and the eyecup 110G to administer therapy.

FIGS. 36A and 36B illustrate another alternative embodiment of thedisposable component 74H that may be employed by the present inventionto apply heat and/or force to the patient's eyelid as part of treatingMGD. This embodiment is similar to the disposable component 74E of FIG.33 in that separate upper and lower eyecups 530A, 530B are provided toapply force to the upper and lower eyelid of the patient. However, botheyecups 530A, 530B do not have to be engaged. Each can be engagedseparately. For example, it may be desired to treat the meibomian glandsin only the upper or lower eyelid of a patient and not both at the sametime. In this manner, the lid warmer platform 94H contains a hinge 534.The upper and lower eyecups 530A, 530B are attached to the hinge 534such that they can rotate over the lid warmer platform 94H. When not inuse, the eyecups 580A, 580B can be rotated away from the lid warmerplatform 94H as illustrated in FIG. 36A. The lid warmer platform 94Econtains a grooved surface 531 that allows the eyecups 530A, 530B to berotated about hinge 534 and moved to the outside surface of the lens 92Has illustrated in FIG. 36B. When in use, the eyecups 580A, 580B movepast a notch 533 in the lid warmer platform 94H to lock in place.

FIG. 37 illustrates another alternative embodiment of the disposablecomponent 74I that may be employed by the present invention to applyheat and/or force to the patient's eyelid as part of treating MGD. Inthis embodiment, the eyecup 110I is formed by eyecup 540 that supports amembrane or bladder 541 to apply force to the patient's eyelid. Theeyecup 540 contains an opening 542 through the lid warmer platform 94Iand extends through to attach the eyecup 110I to the lid warmer platform94I when the disposable component 74I is installed. The lid warmerplatform 94I contains a thickened surface 543 which locks the lid warmerplatform 94I into the split 542 and prevents the eyecup 101I from movingabout the lid warmer platform 94I for a secure fit when in use. A handle544 is also attached to the eyecup 540 to allow a technician to hold theeyecup 540 when adjusting the lid warmer 901 with respect to the eyecup540.

FIGS. 38A and 38B illustrate another alternative embodiment of thedisposable component 74J that may be employed by the present inventionto apply heat and/or force to the patient's eyelid as part of treatingMGD. In this embodiment, the eyecup 110J is provided as one piece. Theeyecup 110J supports a membrane or bladder 551 to apply force to apatient's eyelid and contains a ridge 552 through which an orifice 554protrudes through. A bladder advance mechanism 554 is placed through theorifice 554, wherein the lid warmer platform 94J extends through theorifice 554 in the bladder advance mechanism 556. The bladder (notshown) is attached to the bladder advance mechanism 556. When it isdesired to advance the bladder (not shown) to the patient's eyelid toapply force, the bladder advance mechanism 556 is rotated such thatnotch 558 can fit inside a groove 557 on the ridge 552 to allow thebladder advance mechanism 556 to move forward through the orifice 552towards the lid warmer 90J and lock in place. When desired to move thebladder away from the lid warmer 90J, the bladder advance mechanism 556is pulled back so that the notch 558 is removed from the groove 557 andcan be rotated away from the groove 557 to be supported by the ridge552.

FIG. 39 illustrates another alternative embodiment of the disposablecomponent 74K that may be employed by the present invention to applyheat and/or force to the patient's eyelid as part of treating MGD. Inthis embodiment, the eyecup 110K is provided as one piece. The eyecup110K supports a membrane or bladder 561 that applies force to thepatient's eyelid. The eyecup 110K contains an outer surface 560 thatcontains rib structures 562A, 562B to support an orifice chamber 564having an orifice 566 through which the lid warmer platform 94K extendsto attach the eyecup 110K to the lid warmer 90K. Squeezable eyecupplatforms 568, 570 are attached on each side of the orifice 566 to therib structures 562A, 562B on one end and to a common hinge 572 on theirother end. When the eyecup platforms 568, 570 are squeezed, it allowsthe lid warmer platform 94K to be move transversally through the orifice566. When the eyecup 110K is to be placed against the patient's eyelid,a grip 578 is pulled such that a neck 576 of the lid warmer platform 94Kis inserted and locked down into a groove 574 formed in the lower eyecupplatform 570.

FIG. 40 illustrates another alternative embodiment of the disposablecomponent 74L that may be employed by the present invention to applyheat and/or force to the patient's eyelid as part of treating MGD. Inthis embodiment, the eyecup 110L and lid warmer 94L are provided as twoseparate pieces. Finger tabs 588A, 588B, attached to hinge 590, can bedepressed to allow room for an opening 482 in the eyecup 110L to beinserted over top the lid warmer platform 94L along opening 582 in theeyecup 580 where desired. When the eyecup 110L is placed on the lidwarmer platform 94L in the desired location, the finger tabs 588A, 558Bare released and the tabs 588A, 588B position and hold the eyecup 110Lin place.

Although the present application discusses and provides devices forapplying heat on the inside of the eyelid and force to the outside ofthe eyelid to treat MGD, other configurations are possible. Heat andforce may be applied in a number of different combinations and mannersto treat MGD. For example, FIG. 41 illustrates an alternative embodimentof the present invention for applying heat and force to tissue proximatea patient's meibomian gland to treat MGD. In this embodiment, heat isapplied and force is applied. Heat is applied provide conductive heattransfer to the meibomian glands to the desired temperature level (step600). For example, heat may be applied to raise the temperature at theinside of the eyelid between 43-47 degrees Celsius. The heat may also beregulated, meaning that a heating means or element is controlled to bewithin the temperatures and means that are safe for the eyelid and at asufficient temperature for melting, loosening, or softening an occlusionor obstruction in the meibomian gland.

A force may also be applied to tissue proximate the patient's meibomiangland to increase the efficiency of heat transfer. As previouslydescribed, the application of force towards the heat source with thepatient's eyelid “sandwiched” therebetween provides greater surfacecontact between the heat source and the eyelid for more efficientconductive heat transfer. Further, the application of force reducesblood flow in the eyelids to reduce convective heat loss through theeyelids and allow the temperature at the meibomian glands to not onlyrise to higher levels, but do so more quickly and efficiently (step602).

The heat and/or force may be maintained for a period of time sufficientto raise the temperature at the meibomian glands sufficient to melt,loosen, or soften the obstructions or occlusions (step 604). The forcemay be maintained after heat is removed, or vice versa depending on thetreatment technique desired. Maintaining force after heat is removed mayreduce convective heat loss at the meibomian glands and thus keep thetemperature level at the meibomian glands to the therapeutic levels formore time than if the force was removed. Maintaining heat withoutmaintaining force may be employed to allow blood flow in the eyelids,such as between successive treatments. For example, it may be desirableto maintain heat to lessen the total amount of treatment time whileapplying and removing force between treatments. Also, it may not benecessary to apply significant amounts of force, or for the sameduration as application of heat, if the obstruction or occlusion islocated in close proximity to the lid margin rather than in the deeperportions of the meibomian gland. Thereafter, either during heatingand/or the application of force or after either, obstructions orocclusions in the meibomian glands may be expressed so that sebum flowis restored from the glands to establish a sufficient lipid layer (step606).

The force may be regulated, meaning that a force generating means iscontrolled to be within the pressure ranges that are safe to be appliedto tissue proximate the meibomian glands and at sufficient pressure toallow the temperature at the meibomian gland to be raised sufficiently.The force may be applied during heating, after heating, or both duringand after heating. In either case, the force may assist in expressingocclusions or obstructions when in a loosened, softened, or melted statefrom the meibomian glands. The force may include vibratory type forces,including those generated mechanically or using fluid type devices ormechanisms. The level of force needed to express obstructions orocclusions in the glands may be greatly reduced when heat is applied tothe obstructions or occlusions to place them in a melted, softened, orloosened state.

The application of force can also stimulate the movement of fluids orsuspensions of occlusions or obstructions from the glands. The presentinvention can be used with devices which generally apply a regulatedforce or milking action to the eyelid to express the fluids orsuspensions or to otherwise mechanically stimulate the movement offluids from the glands. In some instances, a small, gentle, continuousforce applied to the eyelid will assist in expression of the fluids andsuspensions. Vibration can also be used when applying forcesimultaneously or immediately after the heating to further assist in theexpression.

Any device may be employed to generate heat on the outside of thepatient's eyelid, including those described herein. Other devices may beemployed, such as the apparatus disclosed in U.S. Patent ApplicationPublication No. 2007/1016254, entitled “Method and apparatus fortreating gland dysfunction employing heated medium,” and incorporatedherein by reference in its entirety. In this application, an apparatusis employed to apply heat to the outside of the patient's eyelid viaheated fluid transfer. Further, a gas may be employed as opposed tofluid to apply heat to the patient's eyelid.

Just as discussed above in the flowchart of FIG. 6, where only heat isapplied, regulated heat can include controlling heat according to atemperature profile. The temperature profile may be a constanttemperature, include ramp-ups, ramp-downs, peaks and valleys. Further,the temperature profile may include heat pulses or be modulated withvarious characteristics, including the use of pulse width modulation(PWM) techniques. The use of modulated heat may allow the temperature tobe raised even higher at the eyelid without damage to the patient'seyelid since the increased temperatures are applied for shorter periodsof time. Obstructions or occlusions in the meibomian glands may havemelting, loosening, or softening points that are beyond temperaturesthat may be applied without the use of modulated heat. The temperatureneeded to melt, loosen, or soften obstructions or occlusions may dependon how keratinized the obstruction or occlusion is. Not all obstructionsor occlusions have the same melting, loosening, or softening points. Byexample only, elevated temperatures between 47 and 55 degrees Celsiusmay be possible when applying modulated heat, especially if the eyelidhas been anesthetized.

The regulated heat can be maintained at a therapeutic temperature for atreatment period. The treatment period can be approximately 1 to 10minutes for example, since the application of force may reduce theamount of time it takes for the heat source to raise the temperature atthe meibomian glands to the desired level. The heat could also berepeatedly applied and maintained for a desired period of time to keepthe occlusion or obstruction in a melted, loosened, or softened state.Either during or after such treatment by regulated heat, mechanicalexpression of lipids and other fluids from the meibomian glands has beenfound to clear obstructions which have essentially melted or been placedin a suspension state (by virtue of melting materials binding solidstogether).

Optionally, after expression of the occlusions or obstructions isperformed (step 606), an optional pharmacological agent may be appliedto the meibomian gland to promote the free flow of sebum and/or reduceor prevent inflammation or infections of the eye or eyelids (step 608).The previous discussion in the flowcharts of FIGS. 6 and 8 regarding useof pharmacological agents above is equally applicable for thisembodiment and thus will not be repeated here. Those compounds areillustrative examples of appropriate pharmacological agents, but thoseskilled in the art will appreciate that other pharmacological compoundsmay be utilized.

FIG. 42 illustrates an alternative embodiment of the present inventionfor applying heat and force to a patient's eyelid to treat MGD. In thisembodiment, heat is applied to the outside of the eyelid and force isapplied to the inside of the eyelid. Heat is applied to the outside ofthe eyelid to provide conductive heat transfer to the meibomian glandsto the desired temperature level (step 610). For example, heat may beapplied to raise the temperature at the inside of the eyelid to between43-47 degrees Celsius. The heat may also be regulated, meaning that aheating means or element is controlled to be within the temperatures andmeans that are safe for the eyelid and at a sufficient temperature formelting, loosening, or softening an occlusion or obstruction in themeibomian gland.

A force may also be applied to the inside of the eyelid to increase theefficiency of heat transfer. As previously described, the application offorce towards the heat source with the patient's eyelid “sandwiched”therebetween provides greater surface contact between the heat sourceand the eyelid for more efficient conductive heat transfer. Further, theapplication of force reduces blood flow in the eyelids to reduceconvective heat loss through the eyelids and allow the temperature atthe meibomian glands to not only rise to higher levels, but do so morequickly and efficiently (step 612).

The heat and/or force may be maintained for a period of time sufficientto raise the temperature at the meibomian glands to a level sufficientto melt, loosen, or soften the obstructions or occlusions (step 614).The force may be maintained after heat is removed, or vice versadepending on the treatment technique desired. Maintaining force afterheat is removed may reduce convective heat loss at the meibomian glandsand thus keep the temperature level at the meibomian glands to thetherapeutic levels for more time than if the force was removed.Maintaining heat without maintaining force may be employed to allowblood flow in the eyelids, such as between successive treatments. Forexample, it may be desirable to maintain heat to lessen the total amountof treatment time while applying and removing force between treatments.Also, it may not be necessary to apply significant amounts of force, orfor the same duration as application of heat, if the obstruction orocclusion is located in close proximity to the lid margin rather than inthe deeper portions of the meibomian gland. Thereafter, either duringheating and/or the application of force or after either, obstructions orocclusions in the meibomian glands may be expressed so that sebum flowis restored from the glands to establish a sufficient lipid layer (step616).

The force may be regulated, meaning that a force generating means iscontrolled to be within the pressure ranges that are safe to be appliedto the eyelid and at sufficient pressure to allow the temperature at themeibomian gland to be raised sufficiently. The force may be appliedduring heating, after heating, or both during and after heating. Ineither case, the force may assist in expressing occlusions orobstructions when in a loosened, softened, or melted state from themeibomian glands. The force may include vibratory type forces, includingthose generated mechanically or using fluid type devices or mechanisms.The level of force needed to express obstructions or occlusions in theglands may be greatly reduced when heat is applied to the obstructionsor occlusions to place them in a melted, softened, or loosened state.

The application of force can also stimulate the movement of fluids orsuspensions of occlusions or obstructions from the glands. The presentinvention can be used with devices which generally apply a regulatedforce or milking action to the eyelid to express the fluids orsuspensions or to otherwise mechanically stimulate the movement offluids from the glands. In some instances, a small, gentle, continuousforce applied to the eyelid will assist in expression of the fluids andsuspensions. Vibration can also be used when applying forcesimultaneously or immediately after the heating to further assist in theexpression.

Any device may be employed to generate heat on the outside of thepatient's eyelid, including those described herein. Other devices may beemployed, such as the apparatus disclosed in U.S. Patent ApplicationPublication No. 2007/1016254, entitled “Method and apparatus fortreating gland dysfunction employing heated medium,” and incorporatedherein by reference in its entirety. In this application, an apparatusis employed to apply heat to the outside of the patient's eyelid viaheated fluid transfer. Further, a gas may be employed as opposed tofluid to apply heat to the patient's eyelid.

Just as discussed above in the flowchart of FIG. 6, where only heat isapplied, regulated heat can include controlling heat according to atemperature profile. The temperature profile may be a constanttemperature, include ramp-ups, ramp-downs, peaks and valleys. Further,the temperature profile may include heat pulses or be modulated withvarious characteristics, including the use of pulse width modulation(PWM) techniques. The use of modulated heat may allow the temperature tobe raised even higher at the eyelid without damage to the patient'seyelid since the increased temperatures are applied for shorter periodsof time. Obstructions or occlusions in the meibomian glands may havemelting, loosening, or softening points that are beyond temperaturesthat may be applied without the use of modulated heat. The temperatureneeded to melt, loosen, or soften obstructions or occlusions may dependon how keratinized the obstruction or occlusion is. Not all obstructionsor occlusions have the same melting, loosening, or softening points. Byexample only, elevated temperatures between 47 and 55 degrees Celsiusmay be possible when applying modulated heat, especially if the eyelidhas been anesthetized.

The regulated heat can be maintained at a therapeutic temperature for atreatment period. The treatment period can be approximately 1 to 10minutes for example, since the application of force may reduce theamount of time it takes for the heat source to raise the temperature atthe meibomian glands to the desired level. The heat could also berepeatedly applied and maintained for a desired period of time to keepthe occlusion or obstruction in a melted, loosened, or softened state.Either during or after such treatment by regulated heat, mechanicalexpression of lipids and other fluids from the meibomian glands has beenfound to clear obstructions which have essentially melted or been placedin a suspension state (by virtue of melting materials binding solidstogether).

Optionally, after expression of occlusions or obstructions is performed(step 616), an optional pharmacological agent may be applied to themeibomian gland to promote the free flow of sebum and/or reduce orprevent inflammation or infections of the eye or eyelids (step 618). Theprevious discussion in the flowcharts of FIGS. 6 and 8 regarding use ofpharmacological agents above is equally applicable for this embodimentand thus will not be repeated here. Those compounds are illustrativeexamples of appropriate pharmacological agents, but those skilled in theart will appreciate that other pharmacological compounds may beutilized.

FIG. 43 illustrates an alternative embodiment of the present inventionfor applying heat and force to a patient's eyelid to treat MGD. In thisembodiment, heat and force are both applied to the outside of theeyelid. Heat is applied to the outside of the eyelid to provideconductive heat transfer to the meibomian glands to the desiredtemperature level (step 620). For example, heat may be applied to raisethe temperature at the inside of the eyelid between 43-47 degreesCelsius. The heat may also be regulated, meaning that a heating means orelement is controlled to be within the temperatures and means that aresafe for the eyelid and at a sufficient temperature for melting,loosening, or softening an occlusion or obstruction in the meibomiangland.

A force may also be applied to the outside of the eyelid to increase theefficiency of heat transfer. As previously described, the application offorce may provide greater surface contact between the heat source andthe eyelid for more efficient conductive heat transfer. Further, theapplication of force reduces blood flow in the eyelids to reduceconvective heat loss through the eyelids and allow the temperature atthe meibomian glands to not only rise to higher levels, but do so morequickly and efficiently (step 622).

The heat and/or force may be maintained for a period of time sufficientto raise the temperature at the meibomian glands sufficient to melt,loosen, or soften the obstructions or occlusions (step 624). The forcemay be maintained after heat is removed, or vice versa depending on thetreatment technique desired. Maintaining force after heat is removed mayreduce convective heat loss at the meibomian glands and thus keep thetemperature level at the meibomian glands to the therapeutic levels formore time than if the force was removed. Maintaining heat withoutmaintaining force may be employed to allow blood flow in the eyelids,such as between successive treatments. For example, it may be desirableto maintain heat to lessen the total amount of treatment time whileapplying and removing force between treatments. Also, it may not benecessary to apply significant amounts of force, or for the sameduration as application of heat, if the obstruction or occlusion islocated in close proximity to the lid margin rather than in the deeperportions of the meibomian gland. Thereafter, either during heatingand/or the application of force or after either, obstructions orocclusions in the meibomian glands may be expressed so that sebum flowis restored from the glands to establish a sufficient lipid layer (step626).

The force may be regulated, meaning that a force generating means iscontrolled to be within the pressure ranges that are safe to be appliedto the eyelid and at sufficient pressure to allow the temperature at themeibomian gland to be raised sufficiently. The force may be appliedduring heating, after heating, or both during and after heating. Ineither case, the force may assist in expressing occlusions orobstructions when in a loosened, softened, or melted state from themeibomian glands. The force may include vibratory type forces, includingthose generated mechanically or using fluid type devices or mechanisms.The level of force needed to express obstructions or occlusions in theglands may be greatly reduced when heat is applied to the obstructionsor occlusions to place them in a melted, softened, or loosened state.

The application of force can also stimulate the movement of fluids orsuspensions of occlusions or obstructions from the glands. The presentinvention can be used with devices which generally apply a regulatedforce or milking action to the eyelid to express the fluids orsuspensions or to otherwise mechanically stimulate the movement offluids from the glands. In some instances, a small, gentle, continuousforce applied to the eyelid will assist in expression of the fluids andsuspensions. Vibration can also be used when applying forcesimultaneously or immediately after the heating to further assist in theexpression.

Any device may be employed to generate heat on the outside of thepatient's eyelid, including those described herein. Other devices may beemployed, such as the apparatus disclosed in U.S. Patent ApplicationPublication No. 2007/1016254, entitled “Method and apparatus fortreating gland dysfunction employing heated medium,” and incorporatedherein by reference in its entirety. In this application, an apparatusis employed to apply heat to the outside of the patient's eyelid viaheated fluid transfer. Further, a gas may be employed as opposed tofluid to apply heat to the patient's eyelid.

Just as discussed above in the flowchart of FIG. 6, where only heat isapplied, regulated heat can include controlling heat according to atemperature profile. The temperature profile may be a constanttemperature, include ramp-ups, ramp-downs, peaks and valleys. Further,the temperature profile may include heat pulses or be modulated withvarious characteristics, including the use of pulse width modulation(PWM) techniques. The use of modulated heat may allow the temperature tobe raised even higher at the eyelid without damage to the patient'seyelid since the increased temperatures are applied for shorter periodsof time. Obstructions or occlusions in the meibomian glands may havemelting, loosening, or softening points that are beyond temperaturesthat may be applied without the use of modulated heat. The temperatureneeded to melt, loosen, or soften obstructions or occlusions may dependon how keratinized the obstruction or occlusion is. Not all obstructionsor occlusions have the same melting, loosening, or softening points. Byexample only, elevated temperatures between 47 and 55 degrees Celsiusmay be possible when applying modulated heat, especially if the eyelidhas been anesthetized.

The regulated heat can be maintained at a therapeutic temperature for atreatment period. The treatment period can be approximately 1 to 10minutes for example, since the application of force may reduce theamount of time it takes for the heat source to raise the temperature atthe meibomian glands to the desired level. The heat could also berepeatedly applied and maintained for a desired period of time to keepthe occlusion or obstruction in a melted, loosened, or softened state.Either during or after such treatment by regulated heat, mechanicalexpression of lipids and other fluids from the meibomian glands has beenfound to clear obstructions which have essentially melted or been placedin a suspension state (by virtue of melting materials binding solidstogether).

Optionally, after expression of occlusions or obstructions is performed(step 626), an optional pharmacological agent may be applied to themeibomian gland to promote the free flow of sebum and/or reduce orprevent inflammation or infections of the eye or eyelids (step 628). Theprevious discussion in the flowcharts of FIGS. 6 and 8 regarding use ofpharmacological agents above is equally applicable for this embodimentand thus will not be repeated here. Those compounds are illustrativeexamples of appropriate pharmacological agents, but those skilled in theart will appreciate that other pharmacological compounds may beutilized.

FIG. 44 illustrates an alternative embodiment of the present inventionfor applying heat and force to a patient's eyelid to treat MGD. In thisembodiment, heat is applied to both the inner and external surface ofthe patient's eyelid. Force may also be applied to the patient's eyelid.Heat is applied to the both the inside and outside of the eyelid toprovide even more efficient conductive heat transfer to the meibomianglands to the desired temperature level (step 630). For example, heatmay be applied to raise the temperature at the inside of the eyelidbetween 43-47 degrees Celsius. The heat may also be regulated, meaningthat a heating means or element is controlled to be within thetemperatures and means that are safe for the eyelid and at a sufficienttemperature for melting, loosening, or softening an occlusion orobstruction in the meibomian gland.

A force may also be applied to the eyelid to increase the efficiency ofheat transfer. As previously described, the application of force mayprovide greater surface contact between the heat source and the eyelidfor more efficient conductive heat transfer. Further, the application offorce reduces blood flow in the eyelids to reduce convective heat lossthrough the eyelids and allow the temperature at the meibomian glands tonot only rise to higher levels, but do so more quickly and efficiently(step 632).

The heat and/or force may be maintained for a period of time sufficientto raise the temperature at the meibomian glands sufficient to melt,loosen, or soften the obstructions or occlusions (step 634). The forcemay be maintained after heat is removed, or vice versa depending on thetreatment technique desired. Maintaining force after heat is removed mayreduce convective heat loss at the meibomian glands and thus keep thetemperature level at the meibomian glands to the therapeutic levels formore time than if the force was removed. Maintaining heat withoutmaintaining force may be employed to allow blood flow in the eyelids,such as between successive treatments. For example, it may be desirableto maintain heat to lessen the total amount of treatment time whileapplying and removing force between treatments. Also, it may not benecessary to apply significant amounts of force, or for the sameduration as application of heat, if the obstruction or occlusion islocated in close proximity to the lid margin rather than in the deeperportions of the meibomian gland. Thereafter, either during heatingand/or the application of force or after either, obstructions orocclusions in the meibomian glands may be expressed so that sebum flowis restored from the glands to establish a sufficient lipid layer (step636).

The force may be regulated, meaning that a force generating means iscontrolled to be within the pressure ranges that are safe to be appliedto the eyelid and at sufficient pressure to allow the temperature at themeibomian gland to be raised sufficiently. The force may be appliedduring heating, after heating, or both during and after heating. Ineither case, the force may assist in expressing occlusions orobstructions when in a loosened, softened, or melted state from themeibomian glands. The force may include vibratory type forces, includingmechanical or those using fluid type devices or mechanisms. The level offorce needed to express obstructions or occlusions in the glands may begreatly reduced when heat is applied to the obstructions or occlusionsto place them in a melted, softened, or loosened state.

The application of force can also stimulate the movement of fluids orsuspensions of occlusions or obstructions from the glands. The presentinvention can be used with devices which generally apply a regulatedforce or milking action to the eyelid to express the fluids orsuspensions or to otherwise mechanically stimulate the movement offluids from the glands. In some instances, a small, gentle, continuousforce applied to the eyelid will assist in expression of the fluids andsuspensions. Vibration can also be used when applying forcesimultaneously or immediately after the heating to further assist in theexpression.

Any device may be employed to generate heat on the inside and outside ofthe patient's eyelid, including those described herein. Just asdiscussed above in the flowchart of FIG. 6, where only heat is applied,regulated heat can include controlling heat according to a temperatureprofile. The temperature profile may be a constant temperature, includeramp-ups, ramp-downs, peaks and valleys. Further, the temperatureprofile may include heat pulses or be modulated with variouscharacteristics, including the use of pulse width modulation (PWM)techniques. The use of modulated heat may allow the temperature to beraised even higher at the eyelid without damage to the patient's eyelidsince the increased temperatures are applied for shorter periods oftime. Obstructions or occlusions in the meibomian glands may havemelting, loosening, or softening points that are beyond temperaturesthat may be applied without the use of modulated heat. The temperatureneeded to melt, loosen, or soften obstructions or occlusions may dependon how keratinized the obstruction or occlusion is. Not all obstructionsor occlusions have the same melting, loosening, or softening points. Byexample only, elevated temperatures between 47 and 55 degrees Celsiusmay be possible when applying modulated heat, especially if the eyelidhas been anesthetized.

The regulated heat can be maintained at a therapeutic temperature for atreatment period. The treatment period can be approximately 1 to 10minutes for example, since the application of force may reduce theamount of time it takes for the heat source to raise the temperature atthe meibomian glands to the desired level. The heat could also berepeatedly applied and maintained for a desired period of time to keepthe occlusion or obstruction in a melted, loosened, or softened state.Either during or after such treatment by regulated heat, mechanicalexpression of lipids and other fluids from the meibomian glands has beenfound to clear obstructions which have essentially melted or been placedin a suspension state (by virtue of melting materials binding solidstogether).

Optionally, after expression of occlusions or obstructions is performed(step 636), an optional pharmacological agent may be applied to themeibomian gland to promote the free flow of sebum and/or reduce orprevent inflammation or infections of the eye or eyelids (step 638). Theprevious discussion in the flowcharts of FIGS. 6 and 8 regarding use ofpharmacological agents above is equally applicable for this embodimentand thus will not be repeated here. Those compounds are illustrativeexamples of appropriate pharmacological agents, but those skilled in theart will appreciate that other pharmacological compounds may beutilized.

Those skilled in the art will recognize improvements and modificationsto the preferred embodiments of the present invention. Heat as used inthis application can mean the application of thermal energy. Heat may beapplied to the patient's eyelid, related structure, or surroundingtissue using any type of thermal energy. Force may be applied to thepatent's eyelid to apply pressure to the patient's eyelid, relatedstructure, and/or surrounding tissue using any type of force or forcegenerating means or device. All such improvements and modifications areconsidered within the scope of the concepts disclosed herein and theclaims that follow.

1. A system for treating meibomian gland dysfunction, comprising: acontroller; a lid warmer, wherein the lid warmer is adapted to bepositioned behind a patient's eyelid on the external surface of thesclera of a patient's eye, wherein the lid warmer applies heat to aninner surface of a patient's eyelid to a temperature level to melt,loosen, or soften an obstruction in a meibomian gland; and a controllerinterface adapted to couple the controller to the lid warmer, whereinthe controller is further adapted to: send a signal to the lid warmer toapply heat to the inner surface of a patient's eyelid to a temperaturelevel to melt, loosen, or soften an obstruction in a meibomian gland;and maintain the signal to the lid warmer to maintain the heat on theinner surface of the patient's eyelid for a period of time.
 2. Thesystem of claim 1, wherein the controller further comprises a lid warmercontroller that is adapted to control the heating element to control theamount of heat generated by the heating element.
 3. The system of claim2, wherein the lid warmer controller is a pulse width modulatedcontroller.
 4. The system of claim 1, wherein the controller is furtheradapted to check a fuse on the lid warmer controller to determine if thelid warmer has been previously used before sending the signal to the lidwarmer to apply heat to the inner surface of a patient's eyelid to atemperature level to melt, loosen, or soften an obstruction in ameibomian gland.
 5. The system of claim 1, wherein the controllerfurther comprises a therapy timer, wherein the therapy timer controlsthe amount of time the controller sends the signal to the lid warmer toapply heat to the inner surface of a patient's eyelid.
 6. The system ofclaim 5, wherein the controller further comprises a display having atherapy timer display, wherein the controller is adapted to display theamount of time in the therapy timer on the therapy timer display.
 7. Thesystem of claim 1, wherein the lid warmer further comprises atemperature feedback device adapted to measure the temperature level atthe lid warmer, wherein the controller is further adapted to monitor thetemperature level at the lid warmer using the temperature feedbackdevice.
 8. The system of claim 7, wherein the temperature feedbackdevice is comprised of at least one thermistor.
 9. The system of claim7, wherein the controller regulates the signal to the lid warmer toregulate the heat generated by the heating element based on thetemperature level at the lid warmer from the temperature feedbackdevice.
 10. The system of claim 9, wherein the controller is furtheradapted to generate an error and/or disable the signal to the lid warmerto discontinue the generation of heat by the heating element if thetemperature level at the lid warmer exceeds a threshold temperaturelevel.
 11. The system of claim 9, wherein the controller is furtheradapted to generate an error and/or not send the signal to the lidwarmer to have the heating element generate heat if the temperaturelevel at the lid warmer does not initially meet or exceed bodytemperature.
 12. The system of claim 1, wherein the controller furthercomprises a display comprising a temperature level display that displaysthe temperature level at the lid warmer.
 13. The system of claim 1,further comprising a force generating device that is adapted to bepositioned on an external surface a patient's eyelid, wherein the forcegenerating device applies pressure to the external surface of apatient's eyelid.
 14. The system of claim 1, wherein the controllerfurther comprises a pressure controller that is adapted to control theforce generating device to control the amount of pressure generated bythe force generating device.
 15. The system of claim 14, wherein theforce generating device is comprised of an eyecup comprising a bladder,wherein the eyecup is adapted to be positioned on the external surfaceof the patient's eyelid, wherein the pressure controller is adapted toinflate the bladder to apply a force to the external surface of thepatient's eyelid.
 16. The system of claim 13, wherein the controllerfurther comprises a force lever, wherein the pressure controller isfurther adapted to control the pressure generated by the forcegenerating device in response to engagement of the force lever.
 17. Thesystem of claim 13, wherein the controller further comprises a pressurefeedback device adapted to measure the pressure generated by the forcegenerating device, wherein the controller is further adapted tomonitoring the pressure level at the external surface of the patient'seyelid using the pressure feedback device.
 18. The system of claim 17,wherein the controller is further adapted to generate an error and/ordisable pressure generated by the force generating device to discontinuepressure generated at the external surface of the patient's eyelid ifthe pressure generated by the pressure generating device exceeds athreshold pressure level.
 19. The system of claim 1, wherein thecontroller further comprises a display comprising a pressure leveldisplay that displays the pressure applied to the external surface ofthe patient's eyelid.
 20. The system of claim 7, wherein the controllerfurther comprises a data log, and wherein the controller is furtheradapted to store information relating to the temperature levels measuredby the temperature feedback device.
 21. The system of claim 17, whereinthe controller further comprises a data log, and wherein the controlleris further adapted to store information relating to the pressure levelsmeasured by the pressure feedback device.
 22. The system of claim 1,wherein the controller further comprises an energy source to power thecontroller, and wherein the controller is further adapted to generate anerror if the energy source cannot generate a threshold energy amount.23. The system of claim 13, wherein the controller is further adapted toassist in the expression of the obstruction from the meibomian gland bycontrolling the pressure generated by the force generating device. 24.The system of claim 1, wherein the controller is further adapted tomaintain the pressure generating by the force generating device whilethe controller is sending a signal to the lid warmer to generate heat.25. The system of claim 13, wherein the controller is further adapted tomaintain the pressure generated by the force generating device while thecontroller is sending a signal to the lid warmer to generate heat toreduces blood flow in the patient's eyelid to reduce thermal dissipationfrom the eyelid.
 26. The system of claim 1, wherein the controller isfurther adapted to generate a signal to the lid warmer to generate theheat at a temperature level between approximately 35 and 47 degreesCelsius.
 27. The system of claim 1, wherein the controller is furtheradapted to generate a variable signal to the lid warmer to generate theheat at a temperature level between approximately 35 and 55 degreesCelsius.